ICSE – Grade 9 – Physics – Ch 04 – QA

Questions & Answers

ICSE - Grade - 9

Subject: Physics

Chapter - 04 - Pressure in Fluids and Atmospheric Pressure

Types of Questions

MCQ

  1. Thrust is defined as:
    A. Force acting along a surface
    B. Force acting normally on a surface
     C. Force per unit area
     D. Pressure exerted by a liquid
     Answer: B

 

  1. SI unit of thrust is:
    A. Pascal
    B. Dyne
     C. Newton
     D. Atmosphere
     Answer: C

 

  1. Pressure is:
    A. Thrust per unit area
    B. Thrust multiplied by area
     C. Force along a surface
     D. None of these
     Answer: A

 

  1. SI unit of pressure is:
    A. Newton
    B. Pascal
     C. Dyne/cm²
     D. Bar
     Answer: B

 

  1. A sharp knife cuts better than a blunt knife because:
    A. Thrust increases
    B. Area of contact increases
     C. Smaller area produces greater pressure
     D. Pressure decreases
     Answer: C

 

  1. Which of the following increases pressure?
    A. Increase area
    B. Reduce thrust
     C. Reduce area
     D. Decrease gravity
     Answer: C

 

  1. A tractor moves easily in fields because:
    A. Tyres are narrow
    B. Tyres are broad
     C. Thrust is reduced
     D. Pressure is increased
     Answer: B

 

  1. Pressure in a fluid acts:
    A. Only downward
    B. Only upward
     C. Equally in all directions
     D. Only horizontally
     Answer: C

 

  1. Pressure exerted by a liquid column depends on:
    A. Volume of liquid
    B. Shape of container
     C. Height of liquid column
     D. Width of container
     Answer: C

 

  1. Formula for pressure at the base of a liquid column:
    A. P = h × ρ × g
    B. P = h ÷ ρ × g
     C. P = ρ ÷ h × g
     D. P = h × g ÷ ρ
     Answer: A

 

  1. Factors affecting pressure at a point in a liquid:
    A. Depth, density, gravity
    B. Volume, depth, temperature
     C. Area, volume, gravity
     D. None of these
     Answer: A

 

  1. Pressure at a point in a liquid:
    A. Acts in one direction only
    B. Acts equally in all directions
     C. Depends on the container shape
     D. Decreases with depth
     Answer: B

 

  1. Which law states that pressure applied at any point of an enclosed liquid is transmitted equally in all directions?
    A. Archimedes’ Principle
    B. Pascal’s Law
     C. Newton’s Law
     D. Bernoulli’s Principle
     Answer: B

 

  1. Hydraulic press works on the principle of:
    A. Pascal’s Law
    B. Archimedes’ Principle
     C. Law of conservation of energy
     D. Boyle’s Law
     Answer: A

 

  1. A hydraulic jack is used to:
    A. Lift heavy vehicles
    B. Measure pressure
     C. Compress materials
     D. Forecast weather
     Answer: A

 

  1. Hydraulic brakes transmit pressure using:
    A. Compressible gas
    B. Incompressible fluid
     C. Springs
     D. Electricity
     Answer: B

 

  1. Atmospheric pressure at sea level is approximately:
    A. 1 × 10³ Pa
    B. 1 × 10⁵ Pa
     C. 1 × 10⁶ Pa
     D. 1 × 10⁴ Pa
     Answer: B

 

  1. Which of the following phenomena is caused by atmospheric pressure?
    A. Siphon action
    B. Use of straw
     C. Syringe filling
     D. All of these
     Answer: D

 

  1. Barometer measures:
    A. Liquid pressure
    B. Atmospheric pressure
     C. Force
     D. Thrust
     Answer: B

 

  1. Mercury is used in barometers because:
    A. Low density
    B. High density and low vapor pressure
     C. Evaporates quickly
     D. Wet glass
     Answer: B

 

  1. Water cannot be used easily in barometers because:
    A. Low density requires very long column
    B. High density
     C. Does not evaporate
     D. None of these
     Answer: A

 

  1. A Fortin barometer is:
    A. Non-portable
    B. Portable with adjustable cistern
     C. Aneroid barometer
     D. Mercury-free
     Answer: B

 

  1. Aneroid barometer is:
    A. Liquid-based
    B. Non-portable
     C. Portable, no liquid used
     D. Fragile
     Answer: C

 

  1. Atmospheric pressure decreases with:
    A. Depth
    B. Altitude
     C. Gravity
     D. Density
     Answer: B

 

  1. Sudden rise in barometric pressure indicates:
    A. Storm
    B. Rain
     C. Clear weather
     D. Cyclone
     Answer: C

 

  1. Altimeter is a modified:
    A. Mercury barometer
    B. Aneroid barometer
     C. Hydraulic jack
     D. Pascal’s press
     Answer: B

 

  1. Thrust is a:
    A. Vector quantity
    B. Scalar quantity
     C. Both
     D. None
     Answer: A

 

  1. Pressure is a:
    A. Vector quantity
    B. Scalar quantity
     C. Depends on area
     D. None
     Answer: B

 

  1. Dams are thicker at the bottom because:
    A. Pressure decreases with depth
    B. Pressure increases with depth
     C. Volume is more
     D. Shape is wide
     Answer: B

 

  1. Submarines withstand high liquid pressure because:
    A. They are narrow
    B. Built strong to resist pressure
     C. They float
     D. Use hydraulic systems
     Answer: B

 

  1. Skis have narrow edges to:
    A. Reduce pressure
    B. Increase pressure on ice
     C. Reduce friction
     D. Make skiing slower
     Answer: B

 

  1. Camels have broad feet to:
    A. Reduce thrust
    B. Increase pressure
     C. Reduce pressure on sand
     D. Move faster
     Answer: C

 

  1. Pressure depends on thrust and:
    A. Density
    B. Area
     C. Volume
     D. Height
     Answer: B

 

  1. Examples of hydraulic machines include:
    A. Hydraulic jack, press, brakes
    B. Pumps and turbines
     C. Barometer
     D. Syringe
     Answer: A

 

  1. Standard atmospheric pressure in mm Hg:
    A. 76 cm
    B. 76 mm
     C. 760 mm
     D. 106 cm
     Answer: C

 

  1. Pressure in fluids does NOT depend on:
    A. Depth
    B. Density
     C. Shape of container
     D. Gravity
     Answer: C

 

  1. Pressure increases with:
    A. Decrease in depth
    B. Increase in depth
     C. Increase in area
     D. Decrease in thrust
     Answer: B

 

  1. Example of thrust exerted by solid:
    A. Water on container
    B. Book on table
     C. Air on roof
     D. Hydraulic fluid
     Answer: B

 

  1. Example of thrust exerted by gas:
    A. Book on table
    B. Air in balloon
     C. Knife edge
     D. Hydraulic press
     Answer: B

 

  1. Pressure produced by same thrust is more on:
    A. Broad surface
    B. Small surface
     C. Any surface
     D. None
     Answer: B

 

  1. Pressure decreases with:
    A. Increase in thrust
    B. Decrease in area
     C. Increase in area
     D. Increase in depth
     Answer: C

 

  1. Principle used in hydraulic lift:
    A. Pascal’s Law
    B. Archimedes’ Principle
     C. Newton’s Law
     D. Bernoulli’s Principle
     Answer: A

 

  1. Pressure acts perpendicular to:
    A. Motion
    B. Surface
     C. Volume
     D. Depth
     Answer: B

 

  1. Syringe fills due to:
    A. Thrust
    B. Atmospheric pressure
     C. Hydraulic action
     D. Liquid density
     Answer: B

 

  1. Air exerts pressure due to:
    A. Its weight
    B. Its density
     C. Its volume
     D. Its temperature
     Answer: A

 

  1. Pressure at the same depth in a liquid:
    A. Is different in all directions
    B. Is equal at all points
     C. Depends on container shape
     D. None
     Answer: B

 

  1. Hydraulic press is used for:
    A. Lifting vehicles
    B. Compressing materials
     C. Forecasting weather
     D. Measuring atmospheric pressure
     Answer: B

 

  1. Density of liquid affects:
    A. Thrust
    B. Pressure at point
     C. Shape of container
     D. Area
     Answer: B

 

  1. Sudden fall in barometer indicates:
    A. Clear weather
    B. Storm or rain
     C. High altitude
     D. Increase in temperature
     Answer: B

 

  1. Air density decreases with:
    A. Depth
    B. Altitude
     C. Gravity
     D. Humidity
     Answer: B

Fill in the Blanks

  1. Thrust is the total ______ acting normally on a surface.
    Answer: force

 

  1. SI unit of thrust is ______.
    Answer: Newton

 

  1. Pressure is defined as thrust per unit ______.
    Answer: area

 

  1. SI unit of pressure is ______.
    Answer: Pascal

 

  1. 1 Pascal is the pressure when a thrust of 1 Newton is applied on an area of ______.
    Answer: 1 m²

 

  1. Pressure is a ______ quantity.
    Answer: scalar

 

  1. A sharp knife cuts better because the smaller ______ produces greater pressure.
    Answer: area

 

  1. Pressure increases when thrust is ______.
    Answer: increased

 

  1. Pressure decreases when the area of contact is ______.
    Answer: increased

 

  1. Liquids and gases exert pressure in ______ directions.
    Answer: all

 

  1. Pressure exerted by a liquid column is given by the formula ______.
    Answer: P = h × ρ × g

 

  1. In the formula P = h × ρ × g, ρ represents the ______ of the liquid.
    Answer: density

 

  1. In the formula P = h × ρ × g, h represents the ______ of the liquid column.
    Answer: height

 

  1. Pressure in a liquid does not depend on the ______ of the container.
    Answer: shape

 

  1. Pressure at a point in a liquid depends on depth, density, and ______.
    Answer: gravity

 

  1. Pressure at a point in a liquid acts ______ in all directions.
    Answer: equally

 

  1. Pressure increases with ______ in a liquid.
    Answer: depth

 

  1. Pressure is the same at all points at the same ______ in a liquid.
    Answer: depth

 

  1. Pressure depends only on the height of the liquid column and not on the ______ of the container.
    Answer: shape

 

  1. A dam is thicker at the ______ to withstand greater liquid pressure.
    Answer: bottom

 

  1. Submarines are built to withstand high ______ pressure.
    Answer: liquid

 

  1. Pascal’s Law states that pressure applied to an enclosed liquid is transmitted ______ in all directions.
    Answer: equally

 

  1. A hydraulic machine works on the principle of ______.
    Answer: Pascal’s Law

 

  1. A small force on a small piston produces a ______ force on a large piston in a hydraulic machine.
    Answer: large

 

  1. The hydraulic press is also called the ______ press.
    Answer: Bramah

 

  1. Hydraulic jacks are used to lift ______ vehicles.
    Answer: heavy

 

  1. Hydraulic brakes transmit pressure using an ______ fluid.
    Answer: incompressible

 

  1. Atmospheric pressure is the pressure exerted by the ______ above the Earth’s surface.
    Answer: air column

 

  1. Standard atmospheric pressure at sea level is ______ Pa.
    Answer: 1.013 × 10⁵

 

  1. Atmospheric pressure causes phenomena such as sucking a drink through a ______.
    Answer: straw

 

  1. Atmospheric pressure also helps in filling a ______ with liquid.
    Answer: syringe

 

  1. A barometer is used to measure ______ pressure.
    Answer: atmospheric

 

  1. Mercury is used in barometers because it has high density and low ______ pressure.
    Answer: vapor

 

  1. Water is unsuitable for barometers because it requires a very ______ column.
    Answer: long

 

  1. Fortin barometer is ______ and has an adjustable screw.
    Answer: portable

 

  1. Aneroid barometer does not use any ______.
    Answer: liquid

 

  1. Aneroid barometer is ______ and compact.
    Answer: portable

 

  1. Atmospheric pressure decreases with increasing ______.
    Answer: altitude

 

  1. Sudden fall in barometric pressure indicates storm or ______.
    Answer: rain

 

  1. Sudden rise in barometric pressure indicates ______ weather.
    Answer: clear

 

  1. An altimeter is a modified ______ barometer used in aircraft.
    Answer: aneroid

 

  1. Pressure acts perpendicular to the ______.
    Answer: surface

 

  1. A knife produces greater pressure on a surface due to its ______ edge.
    Answer: sharp

 

  1. Tractors have broad tyres to reduce ______ on the ground.
    Answer: pressure

 

  1. Camels have broad feet to reduce pressure on ______.
    Answer: sand

 

  1. Liquids exert pressure due to their weight and continuous random ______ of particles.
    Answer: motion

 

  1. Hydraulic press is used for compressing materials and making ______.
    Answer: bales

 

  1. Hydraulic lift is used in garages to lift heavy ______.
    Answer: vehicles

 

  1. Atmospheric pressure at sea level is also called 1 ______.
    Answer: atmosphere

 

  1. Pressure in liquids depends on depth, density, and ______, but not on container volume.
    Answer: gravity

Name the Following

  1. Name the force acting normally on a surface.
    Answer: Thrust

 

  1. Name the quantity obtained by thrust per unit area.
    Answer: Pressure

 

  1. Name the SI unit of thrust.
    Answer: Newton

 

  1. Name the SI unit of pressure.
    Answer: Pascal

 

  1. Name the law stating that pressure applied to a confined liquid is transmitted equally in all directions.
    Answer: Pascal’s Law

 

  1. Name the instrument used to measure atmospheric pressure using mercury.
    Answer: Mercury barometer

 

  1. Name the portable barometer with adjustable cistern.
    Answer: Fortin barometer

 

  1. Name the barometer that does not use any liquid.
    Answer: Aneroid barometer

 

  1. Name the modified aneroid barometer used in aircraft to measure altitude.
    Answer: Altimeter

 

  1. Name the hydraulic machine used to compress materials.
    Answer: Hydraulic press (Bramah Press)

 

  1. Name the hydraulic machine used to lift heavy vehicles.
    Answer: Hydraulic jack (Hydraulic lift)

 

  1. Name the hydraulic machine used to apply equal braking force on all wheels.
    Answer: Hydraulic brakes

 

  1. Name the quantity that increases with depth in a liquid.
    Answer: Pressure

 

  1. Name the physical factor on which pressure in a liquid depends.
    Answer: Depth, density, gravity

 

  1. Name the phenomena caused by atmospheric pressure when drinking through a straw.
    Answer: Sucking action of a straw

 

  1. Name the phenomena caused by atmospheric pressure when filling a syringe.
    Answer: Suction of liquid into the syringe

 

  1. Name the phenomena caused by atmospheric pressure when filling a fountain pen with ink.
    Answer: Inflow of ink due to suction

 

  1. Name the phenomena caused by atmospheric pressure in the working of a siphon.
    Answer: Siphoning action

 

  1. Name the type of quantity that pressure is.
    Answer: Scalar

 

  1. Name the type of quantity that thrust is.
    Answer: Vector

 

  1. Name the type of motion of liquid particles responsible for pressure in fluids.
    Answer: Random motion

 

  1. Name the SI unit equivalent to 1 N/m².
    Answer: Pascal

 

  1. Name a device that can forecast weather using atmospheric pressure.
    Answer: Barometer

 

  1. Name a natural phenomenon indicated by a sudden fall in barometric pressure.
    Answer: Storm or rain

 

  1. Name a natural phenomenon indicated by a sudden rise in barometric pressure.
    Answer: Clear weather

 

  1. Name the factor which causes atmospheric pressure to decrease with height.
    Answer: Decrease in air density

 

  1. Name the device that measures atmospheric pressure without any liquid.
    Answer: Aneroid barometer

 

  1. Name the part of a hydraulic press where small force is applied.
    Answer: Small piston

 

  1. Name the part of a hydraulic press where large force is obtained.
    Answer: Large piston

 

  1. Name an example of a solid exerting thrust.
    Answer: Book on a table

 

  1. Name an example of a gas exerting thrust.
    Answer: Air in a balloon

 

  1. Name an example of a liquid exerting thrust.
    Answer: Water in a container

 

  1. Name the law that explains why dams are thicker at the bottom.
    Answer: Law of liquid pressure (pressure increases with depth)

 

  1. Name the factor which affects barometric height due to humidity.
    Answer: Air density

 

  1. Name the factor which affects barometric height due to temperature.
    Answer: Density of mercury

 

  1. Name an advantage of mercury as a barometric liquid.
    Answer: High density and low vapor pressure

 

  1. Name a disadvantage of using water in barometers.
    Answer: Requires a very long column and evaporates quickly

 

  1. Name a factor that affects pressure on a surface.
    Answer: Magnitude of thrust or area of contact

 

  1. Name an example where narrow edges increase pressure.
    Answer: Knife or pin

 

  1. Name an example where broad surfaces decrease pressure.
    Answer: Tractor tyres or camel feet

 

  1. Name a device used to measure altitude in aircraft.
    Answer: Altimeter

 

  1. Name the principle behind hydraulic lift.
    Answer: Pascal’s Law

 

  1. Name a hydraulic machine used in garages.
    Answer: Hydraulic jack

 

  1. Name the unit of pressure commonly used in meteorology.
    Answer: Atmosphere (atm)

 

  1. Name the phenomenon where air exerts pressure causing liquid to rise.
    Answer: Atmospheric suction

 

  1. Name an effect of liquid pressure on submarines.
    Answer: Submarines withstand high pressure by strong hulls

 

  1. Name an example of a hydraulic machine used in vehicles.
    Answer: Hydraulic brakes

 

  1. Name a factor that does NOT affect pressure at a point in a liquid.
    Answer: Shape of container

 

  1. Name the standard height of mercury in a barometer at sea level.
    Answer: 76 cm of mercury

 

  1. Name the physical quantity calculated using P = F/A.
    Answer: Pressure

Answer in One Word

  1. The SI unit of thrust.
    Answer: Newton

 

  1. The SI unit of pressure.
    Answer: Pascal

 

  1. The force acting perpendicular to a surface.
    Answer: Thrust

 

  1. The type of quantity pressure is.
    Answer: Scalar

 

  1. The law stating that pressure in a confined liquid is transmitted equally in all directions.
    Answer: Pascal

 

  1. The device used to measure atmospheric pressure using mercury.
    Answer: Barometer

 

  1. A barometer that is portable and has an adjustable screw.
    Answer: Fortin

 

  1. A barometer that does not use any liquid.
    Answer: Aneroid

 

  1. A modified aneroid barometer used in aircraft.
    Answer: Altimeter

 

  1. Hydraulic machine used to compress materials.
    Answer: Press

 

  1. Hydraulic machine used to lift heavy vehicles.
    Answer: Jack

 

  1. Hydraulic machine used to apply braking force on wheels.
    Answer: Brakes

 

  1. The physical factor that increases liquid pressure with depth.
    Answer: Depth

 

  1. A factor affecting pressure at a point in a liquid.
    Answer: Density

 

  1. Another factor affecting liquid pressure at a point.
    Answer: Gravity

 

  1. The height of the mercury column in a standard barometer at sea level.
    Answer: 76

 

  1. The atmospheric pressure at sea level.
    Answer: 1.013e5

 

  1. A sharp edge produces higher pressure due to smaller.
    Answer: Area

 

  1. Pressure decreases if the area of contact is.
    Answer: Larger

 

  1. Tractors have what type of tyres to reduce pressure?
    Answer: Broad

 

  1. Camels have what type of feet to reduce pressure on sand?
    Answer: Broad

 

  1. A syringe works due to what type of pressure?
    Answer: Atmospheric

 

  1. The random motion of liquid particles causes.
    Answer: Pressure

 

  1. Submarines are built to withstand high.
    Answer: Pressure

 

  1. Pascal’s law is the principle behind what type of machine?
    Answer: Hydraulic

 

  1. The small piston in a hydraulic press produces a large force on the.
    Answer: Piston

 

  1. Water is unsuitable for barometers because it.
    Answer: Evaporates

 

  1. The physical quantity calculated using P = F/A.
    Answer: Pressure

 

  1. A hydraulic jack is used to lift.
    Answer: Vehicles

 

  1. Hydraulic brakes transmit pressure using an incompressible.
    Answer: Fluid

 

  1. The factor that decreases atmospheric pressure with height.
    Answer: Altitude

 

  1. Sudden fall in barometric pressure indicates.
    Answer: Storm

 

  1. Sudden rise in barometric pressure indicates.
    Answer: Clear

 

  1. Mercury has low what pressure?
    Answer: Vapor

 

  1. The part of a hydraulic machine where force is applied.
    Answer: Piston

 

  1. The phenomena caused by atmospheric pressure in a straw.
    Answer: Suction

 

  1. The phenomena caused by atmospheric pressure in a syringe.
    Answer: Suction

 

  1. A dam is thicker at the bottom due to increasing.
    Answer: Pressure

 

  1. The instrument that measures pressure without any liquid.
    Answer: Aneroid

 

  1. The unit commonly used in meteorology.
    Answer: Atmosphere

 

  1. The type of motion responsible for liquid pressure.
    Answer: Random

 

  1. The force applied on a small piston produces what force on a large piston?
    Answer: Large

 

  1. Submarines wear specially designed.
    Answer: Suits

 

  1. Liquids are considered what in hydraulic machines?
    Answer: Incompressible

 

  1. Pressure acts perpendicular to the.
    Answer: Surface

 

  1. Hydraulic press is also called the.
    Answer: Bramah

 

  1. Trains and vehicles use broad tyres to reduce.
    Answer: Pressure

 

  1. The effect of decreasing air density with height reduces.
    Answer: Pressure

 

  1. Atmospheric pressure causes liquid to rise due to.
    Answer: Suction

 

  1. Standard atmospheric pressure is equivalent to one.
    Answer: Atmosphere

ICSE - Grade 9 - Physics

All Chapters

  • Chapter 1 Measurement and Experimentation
  • Chapter 2 Motion in one dimension
  • Chapter 3 Laws of Motion
  • Chapter 4 Pressure in fluids and Atmospheric pressure
  • Chapter 5 Upthrust in Fluids, Archimedes’ Principle and Floatation
  • Chapter 6 Heat and energy
  • Chapter 7 Reflection of light
  • Chapter 8 Propagation of Sound waves
  • Chapter 9 Current Electricity
  • Chapter 10 Magnetism

ICSE - Grade 9 - Chemistry

All Chapters

  • Chapter 1 The Language of Chemistry
  • Chapter 2 Chemical Changes and Reactions
  • Chapter 3 Water
  • Chapter 4 Atomic Structure and Chemical Bonding
  • Chapter 5 The periodic table
  • Chapter 6 Study of the first Element Hydrogen
  • Chapter 7 Study of Gas laws
  • Chapter 8 Atmospheric Pollution

ICSE - Grade 9 - Mathematics

All Chapters

  • Chapter 1 Rational and Irrational Numbers
  • Chapter 2 Compound Interest [Without Using Formula]
  • Chapter 3 Compound Interest [Using Formula]
  • Chapter 4 Expansions
  • Chapter 5 Factorisation
  • Chapter 6 Simultaneous Equations
  • Chapter 7 Indices
  • Chapter 8 Logarithms
  • Chapter 9 Triangles
  • Chapter 10 Isosceles Triangles
  • Chapter 11 Inequalities
  • Chapter 12 Midpoint and Its Converse
  • Chapter 13 Pythagoras Theorem
  • Chapter 14 Rectilinear Figures
  • Chapter 15 Construction of Polygons
  • Chapter 16 Area Theorems
  • Chapter 17 Circle
  • Chapter 18 Statistics
  • Chapter 19 Mean and Median
  • Chapter 20 Area and Perimeter of Plane Figures
  • Chapter 21 Solids
  • Chapter 22 Trigonometrical Ratios
  • Chapter 23 Trigonometrical Ratios of Standard Angles
  • Chapter 24 Solutions of Right Triangles
  • Chapter 25 Complementary Angles
  • Chapter 26 Coordinate Geometry
  • Chapter 27 Graphical Solution
  • Chapter 28 Distance Formula

ICSE - Grade 9 - Biology

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  • Chapter 1 Introducing Biology
  • Chapter 2 Cell: The Unit Of Life
  • Chapter 3 Tissues: Plant And Animal Tissue
  • Chapter 4 The Flower
  • Chapter 5 Pollination and Fertilization
  • Chapter 6 Seeds: Structure and Germination
  • Chapter 7 Respiration in Plants
  • Chapter 8 Five Kingdom Classification
  • Chapter 9 Economic Importance of Bacteria and Fungi
  • Chapter 10 Nutrition
  • Chapter 11 Digestive system
  • Chapter 12 Skeleton: Movement and Locomotion
  • Chapter 13 Skin: The Jack of all trades
  • Chapter 14 The Respiratory System
  • Chapter 15 Hygiene: [A key to Healthy Life]
  • Chapter 16 Diseases: Cause and Control
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  • Chapter 18 Health Organizations
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ICSE - Grade 9 - History

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  • Chapter 1 – The Harappan Civilisation
  • Chapter 2 – The Vedic Period
  • Chapter 3 – Jainism and Buddhism
  • Chapter 4 – The Mauryan Empire
  • History — Chapter 5
    The Sangam Age
  • Chapter 6 – The Age of the Guptas
  • Chapter 7 – Medieval India — (A) The Cholas
  • Chapter 8 – Medieval India — (B) The Delhi Sultanate
  • Chapter 9 – Medieval India — (C) The Mughal Empire
  • Chapter 10 – Medieval India — (D) Composite Culture
  • Chapter 11 – The Modern Age in Europe — (A) Renaissance
  • Chapter 12 – The Modern Age in Europe — (B) Reformation
  • Chapter 13 – The Modern Age in Europe — (C) Industrial Revolution
  •  

ICSE - Grade 9 - Civics

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  • Chapter 1: Our Constitution
  • Chapter 2: Salient Features of the Constitution — I
  • Chapter 3: Salient Features of the
  • Constitution — II
  • Chapter 4: Elections
  • Chapter 5: Local Self-Government — Rural
  • Chapter 6: Local Self-Government — Urban
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ICSE - Grade 9 - Geography

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  • Ch 1 – Earth as a Planet
    Ch 2 – Geographic Grid: Latitudes and Longitudes
    Ch 3 – Rotation and Revolution
    Ch 4 – Earth’s Structure
    Ch 5 – Landforms of the Earth
    Ch 6 – Rocks
    Ch 7 – Volcanoes
    Ch 8 – Earthquakes
    Ch 9 – Weathering
    Ch 10 – Denudation
    Ch 11 – Hydrosphere
    Ch 12 – Composition and Structure of the Atmosphere
    Ch 13 – Insolation
    Ch 14 – Atmospheric Pressure and Winds
    Ch 15 – Humidity
    Ch 16 – Pollution
    Ch 17 – Sources of Pollution
    Ch 18 – Effects of Pollution
    Ch 19 – Preventive Measures
    Ch 20 – Natural Regions of the World

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  1. Pascal’s Law, Bramah Press, Hydraulic Jack, Newton’s Law of Motion
    Answer: Newton’s Law of Motion
    Explanation: Others are related to fluid pressure; Newton’s Law of Motion is not.

 

  1. Thrust, Pressure, Density, Gravity
    Answer: Gravity
    Explanation: Thrust, Pressure, and Density are measurable quantities in fluids; Gravity is an acceleration.

 

  1. Mercury Barometer, Fortin Barometer, Aneroid Barometer, Hydraulic Jack
    Answer: Hydraulic Jack
    Explanation: Others measure atmospheric pressure; Hydraulic Jack is a machine.

 

  1. Knife, Nail, Camels’ Feet, Hydraulic Press
    Answer: Hydraulic Press
    Explanation: First three are examples of changing pressure via area; Hydraulic Press is a machine.

 

  1. Depth, Density, Gravity, Volume
    Answer: Volume
    Explanation: Pressure at a point in liquid depends on depth, density, gravity; not volume.

 

  1. Bramah Press, Hydraulic Lift, Hydraulic Brakes, Barometer
    Answer: Barometer
    Explanation: Others are hydraulic machines; Barometer measures pressure.

 

  1. Sharp Knife, Blunt Knife, Pin, Nail
    Answer: Blunt Knife
    Explanation: Others produce high pressure due to sharp points; blunt knife does not.

 

  1. Air, Water, Mercury, Steel
    Answer: Steel
    Explanation: Air, Water, Mercury are fluids; steel is a solid.

 

  1. Hydraulic Jack, Hydraulic Press, Hydraulic Brakes, Straw
    Answer: Straw
    Explanation: Others are hydraulic machines; straw uses atmospheric pressure.

 

  1. Pressure, Thrust, Force, Altimeter
    Answer: Altimeter
    Explanation: Pressure, Thrust, Force are physical quantities; Altimeter is an instrument.

 

  1. Camels’ Feet, Tractors’ Tyres, Knife Edge, Submarine Hull
    Answer: Knife Edge
    Explanation: First three reduce/increase pressure over broad surfaces; knife increases pressure.

 

  1. Mercury, Water, Oil, Steel
    Answer: Steel
    Explanation: First three are liquids; steel is solid.

 

  1. 1 atm, 76 cm Hg, 1 Pascal, 10.4 m water column
    Answer: 1 Pascal
    Explanation: Others represent large pressure units; 1 Pa is very small.

 

  1. Syringe, Straw, Fountain Pen, Hydraulic Press
    Answer: Hydraulic Press
    Explanation: First three demonstrate atmospheric pressure; Hydraulic Press is a machine.

 

  1. Pressure, Depth, Density, Mass
    Answer: Mass
    Explanation: Pressure depends on depth and density; mass alone doesn’t determine it.

 

  1. Bramah Press, Hydraulic Jack, Hydraulic Brakes, Submarine Suit
    Answer: Submarine Suit
    Explanation: First three are machines; suit protects against pressure.

 

  1. Air, Mercury, Water, Steel
    Answer: Steel
    Explanation: Air, Mercury, Water are fluids exerting pressure; steel is solid.

 

  1. Altimeter, Barometer, Thermometer, Fortin Barometer
    Answer: Thermometer
    Explanation: Others measure pressure; thermometer measures temperature.

 

  1. Knife, Pin, Needle, Table
    Answer: Table
    Explanation: Knife, Pin, Needle are pointed and increase pressure; table is flat.

 

  1. Pascal’s Law, Newton’s Law, Hydrostatic Law, Law of Liquid Pressure
    Answer: Newton’s Law
    Explanation: Others are laws of fluid pressure; Newton’s law is about motion.

 

  1. Depth, Density, Gravity, Area
    Answer: Area
    Explanation: Depth, Density, Gravity affect pressure at a point; Area affects pressure on a surface.

 

  1. Syringe, Straw, Fountain Pen, Hydraulic Jack
    Answer: Hydraulic Jack
    Explanation: First three involve atmospheric pressure; Hydraulic Jack is hydraulic.

 

  1. Mercury, Water, Oil, Air
    Answer: Air
    Explanation: Mercury, Water, Oil are liquids; air is gas.

 

  1. Hydraulic Press, Hydraulic Jack, Hydraulic Brakes, Knife Edge
    Answer: Knife Edge
    Explanation: Others are hydraulic machines; knife edge changes pressure by area.

 

  1. Camels’ Feet, Tractors’ Tyres, Knife Edge, Submarine Hull
    Answer: Knife Edge
    Explanation: Others reduce pressure; knife edge increases pressure.

 

  1. Hydraulic Press, Straw, Barometer, Hydraulic Jack
    Answer: Straw
    Explanation: Straw uses atmospheric pressure; others are hydraulic machines.

 

  1. 1 atm, 76 cm Hg, 10.4 m H₂O, 1 Pascal
    Answer: 1 Pascal
    Explanation: Others are large pressure measurements; 1 Pascal is very small.

 

  1. Depth, Density, Gravity, Volume
    Answer: Volume
    Explanation: Pressure at a point does not depend on the volume of the container.

 

  1. Altimeter, Barometer, Fortin Barometer, Hydraulic Press
    Answer: Hydraulic Press
    Explanation: First three measure pressure; Hydraulic Press is a machine.

 

  1. Sharp Knife, Blunt Knife, Pin, Needle
    Answer: Blunt Knife
    Explanation: Others produce high pressure due to sharp points; blunt knife does not.

 

  1. Air, Mercury, Water, Steel
    Answer: Steel
    Explanation: Steel is solid; others are fluids.

 

  1. Syringe, Straw, Fountain Pen, Hydraulic Press
    Answer: Hydraulic Press
    Explanation: First three use atmospheric pressure; Hydraulic Press is hydraulic.

 

  1. Camels’ Feet, Knife Edge, Tractors’ Tyres, Submarine Suit
    Answer: Knife Edge
    Explanation: Knife Edge increases pressure; others reduce or withstand pressure.

 

  1. Bramah Press, Hydraulic Jack, Hydraulic Brakes, Straw
    Answer: Straw
    Explanation: Straw uses atmospheric pressure; others are hydraulic machines.

 

  1. Pressure, Thrust, Density, Altimeter
    Answer: Altimeter
    Explanation: Pressure, Thrust, Density are physical quantities; Altimeter is an instrument.

 

  1. Mercury, Water, Oil, Steel
    Answer: Steel
    Explanation: Steel is a solid; others are fluids.

 

  1. Knife, Pin, Needle, Table
    Answer: Table
    Explanation: Table is flat and reduces pressure; others increase pressure.

 

  1. 1 atm, 76 cm Hg, 1 Pascal, 10.4 m H₂O
    Answer: 1 Pascal
    Explanation: Very small pressure unit compared to others.

 

  1. Syringe, Straw, Fountain Pen, Hydraulic Jack
    Answer: Hydraulic Jack
    Explanation: First three involve atmospheric pressure; Hydraulic Jack is hydraulic.

 

  1. Depth, Density, Gravity, Volume
    Answer: Volume
    Explanation: Volume does not affect pressure at a point.

 

  1. Camels’ Feet, Tractors’ Tyres, Knife Edge, Hydraulic Press
    Answer: Knife Edge
    Explanation: Knife Edge increases pressure; others reduce or transmit pressure.

 

  1. Bramah Press, Hydraulic Jack, Hydraulic Brakes, Straw
    Answer: Straw
    Explanation: Straw works on atmospheric pressure; others are hydraulic machines.

 

  1. Altimeter, Barometer, Fortin Barometer, Thermometer
    Answer: Thermometer
    Explanation: Thermometer measures temperature; others measure pressure.

 

  1. Hydraulic Press, Knife, Pin, Needle
    Answer: Hydraulic Press
    Explanation: Others are small objects increasing pressure by area; press is a machine.

 

  1. Pressure, Thrust, Force, Altimeter
    Answer: Altimeter
    Explanation: Altimeter is an instrument; others are physical quantities.

 

  1. Mercury, Water, Oil, Steel
    Answer: Steel
    Explanation: Steel is solid; others are fluids.

 

  1. Camels’ Feet, Tractors’ Tyres, Knife Edge, Submarine Suit
    Answer: Knife Edge
    Explanation: Knife Edge increases pressure; others reduce or withstand it.

 

  1. Sharp Knife, Blunt Knife, Pin, Needle
    Answer: Blunt Knife
    Explanation: Blunt knife produces less pressure; others produce higher pressure.

 

  1. Syringe, Straw, Fountain Pen, Hydraulic Jack
    Answer: Hydraulic Jack
    Explanation: Hydraulic Jack is a machine; others use atmospheric pressure.

 

  1. 1 atm, 76 cm Hg, 10.4 m H₂O, 1 Pascal
    Answer: 1 Pascal
    Explanation: 1 Pascal is very small compared to other standard pressure units.

Match the Pair

Set 1

Column A

  1. Thrust
  2. Pressure
  3. Pascal’s Law
  4. Hydraulic Jack
  5. Barometer

Column B (Shuffled)
 a. Measures atmospheric pressure
 b. Force per unit area
 c. Force perpendicular to a surface
 d. Principle of transmission of pressure in liquids
 e. Lifts heavy vehicles

Answers:
 1 → c
 2 → b
 3 → d
 4 → e
 5 → a

Set 2

Column A

  1. Fortin Barometer
  2. Aneroid Barometer
  3. Hydraulic Press
  4. Depth in liquid
  5. Density of liquid

Column B (Shuffled)
 a. Portable and liquid-free pressure measurement
 b. Standard atmospheric pressure ~76 cm Hg
 c. More depth increases pressure
 d. Small piston applies force to large piston
 e. Higher density increases pressure

Answers:
 1 → b
 2 → a
 3 → d
 4 → c
 5 → e

Set 3

Column A

  1. Knife Edge
  2. Camels’ Feet
  3. Syringe
  4. Atmospheric Pressure
  5. Hydraulic Brakes

Column B (Shuffled)
 a. Reduces pressure on sand
 b. Equal braking force on all wheels
 c. Sucks liquid due to pressure difference
 d. Sharp edge increases pressure
 e. Pressure of air column above earth

Answers:
 1 → d
 2 → a
 3 → c
 4 → e
 5 → b

Set 4

Column A

  1. Pressure Formula
  2. Standard Atmospheric Pressure
  3. Pressure in Fluids
  4. Submarine Hull
  5. Pascal

Column B (Shuffled)
 a. P = F ÷ A
 b. 1.013 × 10⁵ Pa at sea level
 c. Acts equally in all directions
 d. Withstands high liquid pressure
 e. SI unit of thrust

Answers:
 1 → a
 2 → b
 3 → c
 4 → d
 5 → e

Set 5

Column A

  1. Hydraulic Lift
  2. Sharp Knife
  3. Blunt Knife
  4. Fountain Pen
  5. Altimeter

Column B (Shuffled)
 a. Measures height above sea level
 b. Cuts easily due to smaller area
 c. Uses atmospheric pressure to draw ink
 d. Produces less pressure
 e. Lifts heavy vehicles using small piston

Answers:
 1 → e
 2 → b
 3 → d
 4 → c
 5 → a

Set 6

Column A

  1. Ways to Increase Pressure
  2. Ways to Decrease Pressure
  3. Hydrostatic Pressure
  4. Volume of Liquid
  5. Gravity

Column B (Shuffled)
 a. Reducing area for same thrust
 b. Increasing area for same thrust
 c. P = h × ρ × g
 d. Does not affect pressure at a point
 e. Higher g increases pressure

Answers:
 1 → a
 2 → b
 3 → c
 4 → d
 5 → e

Set 7

Column A

  1. Consequences of Liquid Pressure
  2. Hydraulic Machines
  3. Pressure Depends On
  4. Random Motion
  5. Standard Barometric Height

Column B (Shuffled)
 a. Helps lift vehicles and apply brakes
 b. Dams thicker at bottom
 c. Depth, density, gravity
 d. Causes pressure in liquids and gases
 e. 76 cm Hg

Answers:
 1 → b
 2 → a
 3 → c
 4 → d
 5 → e

Set 8

Column A

  1. Air Column
  2. Siphon
  3. Rubber Sucker
  4. Submarines
  5. Hydraulic Principle

Column B (Shuffled)
 a. Pressure transmitted equally in all directions
 b. Atmospheric pressure removes liquid from one place to another
 c. Atmospheric pressure allows sticking to surfaces
 d. Built to withstand high pressure
 e. Causes atmospheric pressure

Answers:
 1 → e
 2 → b
 3 → c
 4 → d
 5 → a

Set 9

Column A

  1. Pressure at Same Depth
  2. Knife, Pin, Needle
  3. Straws
  4. Broad Tyres
  5. Camels

Column B (Shuffled)
 a. Reduce pressure
 b. Produce high pressure due to small area
 c. Atmospheric pressure enables sucking liquid
 d. Equal pressure at same depth in liquid
 e. Broad feet reduce pressure on sand

Answers:
 1 → d
 2 → b
 3 → c
 4 → a
 5 → e

Set 10

Column A

  1. Factors Affecting Pressure at a Point
  2. Advantages of Mercury
  3. Disadvantages of Water in Barometer
  4. Falling Barometer
  5. Rising Barometer

Column B (Shuffled)
 a. Short column needed, low vapor pressure, does not stick to glass
 b. Storm or rain
 c. Depth, density, gravity
 d. Evaporates easily, requires tall column, wets glass
 e. Clear weather

Answers:
 1 → c
 2 → a
 3 → d
 4 → b
 5 → e

Short Answer Questions  

  1. Define thrust.
     Answer: Thrust is the total force acting perpendicular to a surface.


  2. What is pressure?
     Answer: Pressure is the thrust acting per unit area of a surface.


  3. State the SI unit of thrust.
     Answer: The SI unit of thrust is Newton (N).


  4. State the SI unit of pressure.
     Answer: The SI unit of pressure is Pascal (Pa).


  5. Write the formula for pressure.
     Answer: Pressure = Thrust ÷ Area.


  6. Give an example of high pressure due to small area.
     Answer: A sharp knife cuts better than a blunt knife due to smaller area at the edge.


  7. Give an example of low pressure due to large area.
     Answer: Tractors have broad tyres to reduce pressure on soft ground.


  8. What are the factors affecting pressure?
     Answer: Pressure depends on thrust and area of contact.


  9. How can pressure be increased?
     Answer: Pressure can be increased by reducing the area for the same thrust.


  10. How can pressure be decreased?
     Answer: Pressure can be decreased by increasing the area for the same thrust.


  11. State Pascal’s Law.
     Answer: Pressure applied at any point of an enclosed liquid is transmitted equally in all directions.


  12. Give one application of Pascal’s Law.
     Answer: Hydraulic machines like hydraulic press and hydraulic jack use Pascal’s Law.


  13. What is a hydraulic press used for?
     Answer: A hydraulic press is used to compress materials and produce large forces.


  14. What is a hydraulic jack used for?
     Answer: A hydraulic jack is used to lift heavy vehicles using a small force.


  15. What is a hydraulic brake?
     Answer: Hydraulic brakes are used in vehicles to apply equal braking force on all wheels.


  16. Why do liquids exert pressure in all directions?
     Answer: Liquids exert pressure in all directions due to random motion of particles and weight of the liquid above.


  17. Write the formula for pressure exerted by a liquid column.
     Answer: P = h × ρ × g, where h is height, ρ is density, and g is acceleration due to gravity.


  18. On what factors does pressure at a point in a liquid depend?
     Answer: It depends on depth, density of the liquid, and acceleration due to gravity.


  19. State the law of liquid pressure regarding equal depth.
     Answer: Pressure is the same at all points at the same depth in a liquid.


  20. Why are dams thicker at the bottom?
     Answer: Dams are thicker at the bottom because pressure increases with depth.


  21. Why do submarines have strong hulls?
     Answer: Submarines have strong hulls to withstand high pressure at greater depths.


  22. Define atmospheric pressure.
     Answer: Atmospheric pressure is the pressure exerted by the air column above the Earth’s surface.


  23. What is the standard value of atmospheric pressure at sea level?
     Answer: The standard value is 1.013 × 10⁵ Pa (1 atmosphere).


  24. How does atmospheric pressure vary with altitude?
     Answer: Atmospheric pressure decreases with increase in altitude.


  25. Name an instrument used to measure atmospheric pressure without using liquid.
     Answer: Aneroid barometer.


  26. Name the portable barometer with a cistern and adjustable screw.
     Answer: Fortin barometer.


  27. Why is mercury preferred in barometers?
     Answer: Mercury is preferred due to its high density, low vapor pressure, and not sticking to glass.


  28. Why is water not ideal for barometers?
     Answer: Water requires a very long column, evaporates quickly, and wets glass.


  29. What does a falling barometer indicate?
     Answer: A falling barometer indicates storm or rain.


  30. What does a rising barometer indicate?
     Answer: A rising barometer indicates clear weather.


  31. What is the principle behind a hydraulic lift?
     Answer: A small force on a small piston is transmitted to a large piston, lifting heavy loads.


  32. Why do camels have broad feet?
     Answer: Camels have broad feet to reduce pressure on sand.


  33. Why do skis have narrow edges?
     Answer: Narrow edges increase pressure to cut through ice.


  34. What is the advantage of using broad straps on school bags?
     Answer: Broad straps decrease pressure on shoulders.


  35. Give an example showing atmospheric pressure in daily life.
     Answer: Sucking a drink through a straw demonstrates atmospheric pressure.


  36. How does a fountain pen work using atmospheric pressure?
     Answer: Atmospheric pressure pushes ink into the pen when air pressure outside is higher than inside.


  37. Why is pressure independent of the shape of the container?
     Answer: Pressure depends only on the height of the liquid column, not on container shape.


  38. What is the unit of barometric pressure?
     Answer: The unit is millimeters of mercury (mm Hg) or Pascal (Pa).


  39. Name three hydraulic machines.
     Answer: Hydraulic press, hydraulic jack, and hydraulic brakes.


  40. How does depth affect liquid pressure?
     Answer: Greater depth results in higher liquid pressure.


  41. How does density affect liquid pressure?
     Answer: Higher density of the liquid increases pressure at a point.


  42. How does gravity affect liquid pressure?
     Answer: Higher acceleration due to gravity increases pressure.


  43. Why do nails and pins have pointed tips?
     Answer: Pointed tips increase pressure, making them easier to penetrate surfaces.


  44. What is meant by hydrostatic pressure?
     Answer: Hydrostatic pressure is the pressure exerted by a liquid at rest due to its weight.


  45. Why are submarines designed to withstand pressure?
     Answer: To prevent crushing by the high pressure of water at depth.


  46. How does a siphon work using atmospheric pressure?
     Answer: Atmospheric pressure pushes liquid from higher to lower level through the tube.


  47. What is the function of an altimeter in aircraft?
     Answer: An altimeter measures height above sea level using atmospheric pressure.


  48. Why are hydraulic machines useful in industries?
     Answer: They can multiply small forces to perform heavy tasks efficiently.


  49. How does a knife edge produce greater pressure?
     Answer: Smaller contact area produces greater pressure for the same thrust.


  50. Name a phenomenon that demonstrates atmospheric pressure at home.
     Answer: Filling a syringe with liquid demonstrates atmospheric pressure.

Puzzles

  1. Puzzle: I am the force that acts perpendicular to a surface. What am I?
     Answer: Thrust


  2. Puzzle: I am a quantity equal to thrust per unit area. Who am I?
     Answer: Pressure


  3. Puzzle: I am the SI unit of pressure. Name me.
     Answer: Pascal (Pa)


  4. Puzzle: I increase if the thrust increases and decrease if the contact area increases. What am I?
     Answer: Pressure


  5. Puzzle: I allow a small force to produce a large force using liquid. What machine am I?
     Answer: Hydraulic press


  6. Puzzle: I am used to lift heavy vehicles in garages using a small piston. Name me.
     Answer: Hydraulic jack


  7. Puzzle: I am used in vehicles to transmit braking force equally to all wheels. Who am I?
     Answer: Hydraulic brakes


  8. Puzzle: I am a liquid column that exerts pressure due to my height. What am I called?
     Answer: Hydrostatic pressure


  9. Puzzle: I act in all directions at a point inside a liquid. Who am I?
     Answer: Liquid pressure


  10. Puzzle: I depend on depth, density, and gravity but not on volume. Who am I?
     Answer: Pressure in a liquid


  11. Puzzle: I am thinner at the top and thicker at the bottom to resist liquid pressure. What am I?
     Answer: Dam


  12. Puzzle: I measure atmospheric pressure using mercury. Name me.
     Answer: Mercury barometer


  13. Puzzle: I measure atmospheric pressure without using liquid. Who am I?
     Answer: Aneroid barometer


  14. Puzzle: I am a portable barometer with an adjustable screw. Name me.
     Answer: Fortin barometer


  15. Puzzle: I decrease with increase in altitude. Who am I?
     Answer: Atmospheric pressure


  16. Puzzle: I am used in aircraft to measure altitude above sea level. What am I?
     Answer: Altimeter


  17. Puzzle: I allow you to drink through a straw by my action. What am I?
     Answer: Atmospheric pressure


  18. Puzzle: I help ink flow into a fountain pen. What am I?
     Answer: Atmospheric pressure


  19. Puzzle: I am the formula P = h × ρ × g. What do I calculate?
     Answer: Pressure exerted by a liquid column


  20. Puzzle: I am a force multiplied by area in hydraulic machines. What principle am I based on?
     Answer: Pascal’s Law


  21. Puzzle: I have a high density, low vapor pressure, and do not stick to glass. Who am I?
     Answer: Mercury


  22. Puzzle: I require a very long column (~10.4 m) to measure atmospheric pressure. Who am I?
     Answer: Water (as barometric liquid)


  23. Puzzle: I allow pressure to be transmitted equally and undiminished in all directions in liquids. Who am I?
     Answer: Pascal’s Law


  24. Puzzle: I am created when you push a plunger in a syringe. What am I?
     Answer: Reduced pressure inside the syringe


  25. Puzzle: I act on all sides of a point in a liquid and remain equal in all directions. Who am I?
     Answer: Hydrostatic pressure


  26. Puzzle: I am why a knife cuts paper easily. What concept explains me?
     Answer: High pressure due to small contact area


  27. Puzzle: I prevent a heavy bag from hurting your shoulder. What principle is applied?
     Answer: Pressure decreases with increased area


  28. Puzzle: I am why tractors move easily in fields. Which concept is this?
     Answer: Reduced pressure due to broad tyres


  29. Puzzle: I push liquid from higher to lower level through a tube. What system am I?
     Answer: Siphon system


  30. Puzzle: I help remove oil from a sealed can. Who am I?
     Answer: Atmospheric pressure


  31. Puzzle: I am why submarines are cylindrical in shape. What am I resisting?
     Answer: High liquid pressure


  32. Puzzle: I am the small piston in a hydraulic lift. What is my role?
     Answer: Apply small force to generate large output force


  33. Puzzle: I am the large piston in a hydraulic press. What is my role?
     Answer: Receive transmitted pressure to produce large force


  34. Puzzle: I am the height of mercury in a barometer at sea level. What is my value approximately?
     Answer: 76 cm of Hg


  35. Puzzle: I am the standard value of atmospheric pressure at sea level. Name me.
     Answer: 1.013 × 10⁵ Pa or 1 atmosphere


  36. Puzzle: I show clear weather when I rise suddenly. What am I?
     Answer: Barometer reading


  37. Puzzle: I show rain or storm when I fall suddenly. What am I?
     Answer: Barometer reading


  38. Puzzle: I act due to the random motion of particles in a liquid. What am I?
     Answer: Pressure in liquid


  39. Puzzle: I increase when the liquid is denser. Who am I?
     Answer: Hydrostatic pressure


  40. Puzzle: I increase when depth increases. Who am I?
     Answer: Pressure in liquid


  41. Puzzle: I increase when gravity increases. Who am I?
     Answer: Pressure in liquid


  42. Puzzle: I act perpendicular to any surface. What am I called?
     Answer: Thrust


  43. Puzzle: I am inversely proportional to area for a given force. Who am I?
     Answer: Pressure


  44. Puzzle: I allow small input force to lift vehicles in garages. What machine am I?
     Answer: Hydraulic jack


  45. Puzzle: I allow compression of metals and materials in factories. What machine am I?
     Answer: Hydraulic press


  46. Puzzle: I transmit pressure through incompressible fluid in vehicles. What am I?
     Answer: Hydraulic brakes


  47. Puzzle: I am why air exerts force on all objects on Earth. What am I called?
     Answer: Atmospheric pressure


  48. Puzzle: I decrease with height above sea level. Who am I?
     Answer: Atmospheric pressure


  49. Puzzle: I am measured using an aneroid or mercury barometer. Who am I?
     Answer: Atmospheric pressure


  50. Puzzle: I am the principle behind lifting heavy objects using fluids. What is my name?
     Answer: Pascal’s Law

Difference Between:

  1. Difference between Thrust and Pressure
     Answer: Thrust is the total force acting perpendicular to a surface. Pressure is the thrust acting per unit area of the surface. Thrust is measured in Newtons (N), while pressure is measured in Pascals (Pa).


  2. Difference between Pascal’s Law and Hydrostatic Law
     Answer: Pascal’s Law states that pressure applied at any point of an enclosed liquid is transmitted equally in all directions. Hydrostatic law states that pressure at a point in a liquid depends on depth, density, and gravity, and acts equally in all directions.


  3. Difference between Primary and Secondary Hydraulic Machines
     Answer: Primary hydraulic machines like a hydraulic press directly use force multiplication. Secondary machines like hydraulic brakes transmit applied pressure to control motion in vehicles.


  4. Difference between Mercury Barometer and Fortin Barometer
     Answer: Mercury barometer measures atmospheric pressure using a simple mercury column, while Fortin barometer is portable with an adjustable cistern for accurate readings.


  5. Difference between Aneroid Barometer and Mercury Barometer
     Answer: Aneroid barometer does not use liquid and is portable. Mercury barometer uses mercury, is fragile, and requires a fixed column.


  6. Difference between Pressure in Solids and Liquids
     Answer: Pressure in solids depends on thrust and area, while pressure in liquids depends on depth, density, and gravity. Pressure in solids acts perpendicular to surface; in liquids, it acts equally in all directions.


  7. Difference between Atmospheric Pressure and Liquid Pressure
     Answer: Atmospheric pressure is due to the weight of the air column above the surface, whereas liquid pressure is due to weight of liquid above a point and particle motion.


  8. Difference between Thrust on Broad Area and Narrow Area
     Answer: Broad area reduces pressure for the same thrust, while narrow area increases pressure, making effects like cutting easier.


  9. Difference between Hydraulic Jack and Hydraulic Press
     Answer: Hydraulic jack lifts vehicles using small piston and multiplies force on large piston. Hydraulic press compresses materials using small piston to apply large force on larger piston.


  10. Difference between Depth and Density Effects on Pressure
     Answer: Depth increases pressure because weight of liquid above increases. Density increases pressure because more mass per unit volume increases weight. Both are directly proportional to pressure.


  11. Difference between Force and Pressure
     Answer: Force is a vector quantity causing acceleration. Pressure is scalar, measuring force per unit area. Force acts in a direction, pressure acts perpendicular to a surface.


  12. Difference between Siphon and Syringe Operation
     Answer: Siphon works by atmospheric pressure pushing liquid from higher to lower level. Syringe works by creating low pressure inside; atmospheric pressure pushes liquid in.


  13. Difference between Hydrostatic Pressure and Hydraulic Pressure
     Answer: Hydrostatic pressure exists due to weight of liquid column. Hydraulic pressure refers to applied pressure transmitted equally in all directions to perform work.


  14. Difference between Altimeter and Barometer
     Answer: Altimeter is a modified aneroid barometer used in aircraft to measure altitude. Barometer measures atmospheric pressure for weather prediction or general measurements.


  15. Difference between High Pressure and Low Pressure Weather Systems
     Answer: High-pressure systems are stable and cause clear weather. Low-pressure systems are unstable and often cause storms or rain.


  16. Difference between Solid Point Contact and Broad Contact
     Answer: Point contact has smaller area and produces high pressure (e.g., needle). Broad contact spreads force, producing low pressure (e.g., snowshoe).


  17. Difference between Atmospheric Pressure at Sea Level and Mountain Top
     Answer: At sea level, air density is higher, giving standard pressure of 1.013 × 10⁵ Pa. On mountain top, air density is lower, giving reduced pressure.


  18. Difference between Liquid Column Pressure and Container Shape
     Answer: Pressure depends on height of liquid column, not on shape of container. Same height gives same pressure irrespective of container width or shape.


  19. Difference between Pressure Transmission in Solids and Fluids
     Answer: In solids, force is transmitted through molecular contact, pressure may vary with direction. In fluids, applied pressure is transmitted equally in all directions (Pascal’s Law).


  20. Difference between Sharp Knife and Blunt Knife Cutting
     Answer: Sharp knife has smaller contact area, producing higher pressure for same force, cutting easily. Blunt knife has larger area, producing lower pressure, cutting with difficulty.

Assertion and Reason


  1. Assertion (A): Pressure in a liquid increases with depth.
    Reason (R): The weight of the liquid column above increases with depth.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure at a point in a liquid acts equally in all directions.
    R: Particles in a liquid move randomly in all directions.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure depends only on the height of the liquid column, not on the shape of the container.
    R: Liquid pressure is affected by volume of the liquid.
     Answer: A is correct, R is wrong.

 


  1. A: A sharp knife cuts better than a blunt knife.
    R: Smaller area at the knife edge produces greater pressure for the same thrust.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Hydraulic press works using Pascal’s Law.
    R: Pressure applied to a confined liquid is transmitted equally in all directions.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Atmospheric pressure decreases with height.
    R: Air density decreases with altitude.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Submarines are built thicker at the bottom.
    R: Pressure increases with depth in water.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure is a vector quantity.
    R: Pressure acts perpendicular to a surface.
     Answer: A is wrong, R is correct.

 


  1. A: Camels have broad feet.
    R: Broad feet reduce pressure on sand.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Tractors have broad tyres.
    R: Broad tyres increase pressure on soil.
     Answer: A is correct, R is wrong.

 


  1. A: The SI unit of pressure is Pascal.
    R: 1 Pascal = 1 Newton per square meter.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: A syringe works due to atmospheric pressure.
    R: Liquid is sucked when pressure inside the syringe is less than outside.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure depends on the area of contact.
    R: Smaller area produces larger pressure for the same thrust.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure in gases is due to weight of gas only.
    R: Gas molecules move randomly and collide with walls of container.
     Answer: A is wrong, R is correct.

 


  1. A: Hydraulic brakes apply equal force to all wheels.
    R: Liquids are incompressible and transmit pressure equally.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Mercury is preferred in barometers.
    R: Mercury has high density and low vapor pressure.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Water can be used in barometers effectively.
    R: Water requires a very tall column (~10.4 m).
     Answer: A is wrong, R is correct.

 


  1. A: Fortin barometer is portable.
    R: It has an adjustable screw for accuracy.
     Answer: Both A and R are correct; R explains a feature but not the portability.

 


  1. A: Altimeter measures height above sea level.
    R: It is a modified aneroid barometer.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure at all points at the same depth is equal.
    R: The liquid is incompressible.
     Answer: Both A and R are correct; R partially explains, but equal depth principle is key.

 


  1. A: Air exerts pressure on objects.
    R: Air has weight.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: A blunt knife cuts better than a sharp knife.
    R: Sharp edge produces higher pressure.
     Answer: Both A and R are correct; R contradicts A. So, A is wrong.

 


  1. A: Hydraulic jack lifts heavy vehicles using small force.
    R: Small piston transmits pressure to large piston.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure is inversely proportional to area.
    R: For same thrust, smaller area increases pressure.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure in a liquid depends on volume.
    R: Pressure depends on height, density, and gravity.
     Answer: A is wrong, R is correct.

 


  1. A: Hydraulic press is used to compress materials.
    R: Pascal’s law allows small force to produce large force.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Submarines have strong hulls.
    R: To withstand high pressure underwater.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure in fluids acts in one direction only.
    R: Liquid particles move randomly.
     Answer: A is wrong, R is correct.

 


  1. A: A knife cuts better on soft surfaces.
    R: Pressure is thrust per unit area.
     Answer: Both A and R are correct; R explains principle but not material.

 


  1. A: Pressure on large area is smaller for same thrust.
    R: Pressure is directly proportional to area.
     Answer: A is correct, R is wrong.

 


  1. A: Syringe works due to Pascal’s Law.
    R: Pressure applied is transmitted equally.
     Answer: A is wrong, R is correct; atmospheric pressure is responsible.

 


  1. A: Barometer measures atmospheric pressure.
    R: Atmospheric pressure is due to air column weight.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Camels’ broad feet reduce pressure on sand.
    R: Pressure = Thrust ÷ Area.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Hydraulic brakes transmit pressure equally.
    R: Brake fluid is compressible.
     Answer: A is correct, R is wrong; fluid is incompressible.

 


  1. A: A knife produces less pressure than a pin.
    R: Pin has smaller area.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure in a liquid increases with gravity.
    R: P = h × ρ × g.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Depth does not affect liquid pressure.
    R: Pressure = h × ρ × g.
     Answer: A is wrong, R is correct.

 


  1. A: Atmospheric pressure helps in sucking liquid through a straw.
    R: Air pressure outside is greater than inside the straw.
     Answer: Both A and R are correct; R explains A.

 


  1. A: Submarines are thin at the top.
    R: Pressure is less near the surface.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure depends on shape of container.
    R: Pressure depends on height of liquid column.
     Answer: A is wrong, R is correct.

 


  1. A: Fortin barometer provides accurate readings.
    R: It has an adjustable screw and cistern.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Pressure is measured in Newton.
    R: Newton is a unit of thrust.
     Answer: A is wrong, R is correct.

 


  1. A: Tractors move easily with broad tyres.
    R: Broad tyres reduce pressure on soft ground.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: A blunt knife produces higher pressure.
    R: Smaller area increases pressure.
     Answer: A is wrong, R is correct.

 


  1. A: Liquid exerts pressure on walls of the container.
    R: Particles in liquid move randomly.
     Answer: Both A and R are correct; R explains A.

 


  1. A: Hydraulic lift is used in garages.
    R: Small piston transmits pressure to large piston.
     Answer: Both A and R are correct; R is the correct explanation of A.

 


  1. A: Atmospheric pressure decreases at sea level.
    R: Air density decreases with height.
     Answer: A is wrong, R is correct.

 


  1. A: Pressure = Thrust ÷ Area.
    R: Smaller area produces greater pressure.
     Answer: Both A and R are correct; R explains A.

 


  1. A: Hydrostatic pressure depends on depth.
    R: Pressure increases with liquid column height.
     Answer: Both A and R are correct; R explains A.

 


  1. A: Hydraulic press produces large force using small input.
    R: Pascal’s law allows equal transmission of pressure.
     Answer: Both A and R are correct; R is the correct explanation of A.

True or False

  1. Thrust is the total force acting normally on a surface.
     Answer: True


  2. Pressure is a vector quantity.
     Answer: False


  3. Pascal’s Law states that pressure applied at any point of an enclosed liquid is transmitted equally in all directions.
     Answer: True


  4. Pressure in a liquid depends on the volume of the liquid.
     Answer: False


  5. Smaller area for the same thrust produces greater pressure.
     Answer: True


  6. Atmospheric pressure at sea level is approximately 1.013 × 10⁵ Pa.
     Answer: True


  7. A blunt knife produces higher pressure than a sharp knife.
     Answer: False


  8. Hydraulic brakes work using the incompressibility of liquids.
     Answer: True


  9. Submarines are built to withstand high pressure at greater depths.
     Answer: True


  10. Pressure at a point in a liquid acts equally in all directions.
     Answer: True


  11. Depth, density of liquid, and gravity are factors affecting pressure at a point in a liquid.
     Answer: True


  12. The SI unit of thrust is Pascal.
     Answer: False


  13. Pressure = Thrust ÷ Area.
     Answer: True


  14. Camels have broad feet to increase pressure on sand.
     Answer: False


  15. Tractors have broad tyres to reduce pressure on soft ground.
     Answer: True


  16. A hydraulic press can produce a large force using a small input force.
     Answer: True


  17. Pressure in a liquid decreases with depth.
     Answer: False


  18. A syringe works due to atmospheric pressure.
     Answer: True


  19. The standard barometric height of mercury is about 76 cm at sea level and 0°C.
     Answer: True


  20. Altimeter is a modified aneroid barometer used to measure height above sea level.
     Answer: True


  21. Pressure depends only on the height of the liquid column, not the shape of the container.
     Answer: True


  22. Mercury is preferred in barometers because it has low density.
     Answer: False


  23. Water can be easily used in barometers without any issues.
     Answer: False


  24. Hydraulic jack lifts heavy vehicles in garages using Pascal’s Law.
     Answer: True


  25. Pressure in gases is solely due to the weight of the gas.
     Answer: False


  26. The sharper the knife, the smaller the area, and the greater the pressure exerted.
     Answer: True


  27. Atmospheric pressure decreases with increase in altitude.
     Answer: True


  28. Dams are designed to be thinner at the bottom.
     Answer: False


  29. Hydrostatic pressure is directly proportional to the density of the liquid.
     Answer: True


  30. Hydraulic machines include hydraulic press, hydraulic jack, and hydraulic brakes.
     Answer: True


  31. Liquid particles do not exert pressure on walls of the container.
     Answer: False


  32. Fortin barometer is portable and provides accurate readings using an adjustable screw.
     Answer: True


  33. Broad school bag straps increase pressure on shoulders.
     Answer: False


  34. Pressure at all points at the same depth in a liquid is the same.
     Answer: True


  35. Pressure in fluids acts only vertically.
     Answer: False


  36. Syringes, fountain pens, and straws demonstrate the effect of atmospheric pressure.
     Answer: True


  37. Volume of liquid affects pressure at a point in a liquid.
     Answer: False


  38. Density of liquid is directly proportional to the pressure at a point.
     Answer: True


  39. Submarines have thin hulls at the bottom.
     Answer: False


  40. Hydrostatic pressure = height × density × gravity (P = h × ρ × g).
     Answer: True


  41. Hydraulic brakes apply equal braking force on all wheels.
     Answer: True


  42. Pressure decreases when thrust is increased for the same area.
     Answer: False


  43. A blunt needle produces less pressure than a sharp needle for the same thrust.
     Answer: True


  44. Pressure on a surface is independent of area.
     Answer: False


  45. Atmospheric pressure can remove oil from a sealed oil can.
     Answer: True


  46. Hydraulic machines work only with compressible liquids.
     Answer: False


  47. Sudden fall in barometer indicates storm or rain.
     Answer: True


  48. Sudden rise in barometer indicates clear weather.
     Answer: True


  49. Altimeter readings are based on atmospheric pressure.
     Answer: True


  50. Pressure in a liquid depends on the shape of the container.
     Answer: False

Long Answer Questions

  1. Explain the concept of thrust and give its unit.
     Answer: Thrust is the total force acting perpendicular (normal) to a surface. It can be exerted by solids, liquids, or gases. For example, a book placed on a table exerts a thrust equal to its weight on the table. The SI unit of thrust is the Newton (N), defined as the force that produces an acceleration of 1 m/s² in a mass of 1 kg.


  2. Define pressure and state its formula and unit.
     Answer: Pressure is the thrust acting per unit area of a surface. It is a scalar quantity. The formula for pressure is Pressure = Thrust ÷ Area. The SI unit of pressure is Pascal (Pa), where 1 Pascal = pressure when a thrust of 1 Newton is applied normally on an area of 1 m². Other units include dyne/cm², atmosphere (atm), bar, and mm of Hg.


  3. Explain why a sharp knife cuts better than a blunt knife.
     Answer: A sharp knife has a smaller contact area at its edge. For the same thrust, pressure = Thrust ÷ Area, so a smaller area produces greater pressure. Therefore, the sharp knife exerts more pressure on the object being cut, making cutting easier. A blunt knife, having a larger contact area, produces less pressure and cuts poorly.


  4. State the factors affecting pressure on a surface.
     Answer: Pressure depends on two factors: (1) Magnitude of thrust – greater thrust produces greater pressure; (2) Area of contact – smaller area produces greater pressure, while larger area produces smaller pressure.


  5. Describe ways to increase and decrease pressure with examples.
     Answer: Pressure can be increased by reducing the area for the same thrust. Examples: Knife edges are made sharp, nails and pins have pointed tips, skis have narrow edges to cut ice. Pressure can be decreased by increasing the area for the same thrust. Examples: School bags have broad straps, tractors have broad tyres to move easily in fields, camels have broad feet to walk on sand.


  6. Explain pressure in fluids and why it acts in all directions.
     Answer: Liquids and gases exert pressure in all directions on the walls of a container and on any object inside them. This happens due to the continuous random motion of particles and the weight of the fluid above. Pressure acts equally in all directions because the particles collide with the walls and with each other uniformly.


  7. Derive the formula for pressure exerted by a liquid column.
     Answer: Consider a liquid column of height h and density ρ. The weight of liquid above a unit area is W = mass × g = (ρ × volume) × g = ρ × A × h × g. Pressure P = Force ÷ Area = W ÷ A = (ρ × A × h × g) ÷ A = ρ × g × h. Hence, P = h × ρ × g. Pressure depends on height, density, and acceleration due to gravity but not on the shape or volume of the container.


  8. Explain the factors affecting pressure at a point in a liquid.
     Answer: Pressure at a point in a liquid depends on: (1) Depth – more depth produces more pressure; (2) Density of the liquid – higher density produces more pressure; (3) Acceleration due to gravity – higher g increases pressure. Pressure is independent of the volume or shape of the container.


  9. State the laws of liquid pressure.
     Answer: Pressure at a point in a liquid acts equally in all directions.
    Pressure increases with depth.
    Pressure is the same at all points at the same depth.
    Pressure depends only on the height of the liquid column, not on the shape of the container.


  10. Explain why dams are thicker at the bottom.
     Answer: Pressure in a liquid increases with depth. At the bottom of a dam, the water pressure is highest due to the weight of the water above. Therefore, dams are made thicker at the bottom to withstand this high pressure and prevent rupture or leakage.


  11. Describe how submarines are built to withstand high liquid pressure.
     Answer: Submarines operate at great depths where water pressure is very high. Their hulls are made of strong materials and are reinforced in shape to withstand this pressure. The design ensures that pressure is distributed evenly and the submarine does not get crushed.


  12. State Pascal’s Law and explain its significance.
     Answer: Pascal’s Law states that pressure applied at any point of an enclosed liquid is transmitted equally and undiminished in all directions throughout the liquid. This principle allows small forces to be amplified in hydraulic machines, enabling them to lift heavy loads or apply large forces with relatively small input force.


  13. Describe the principle and working of a hydraulic press (Bramah Press).
     Answer: A hydraulic press works on Pascal’s Law. A small force applied on a small piston is transmitted through an incompressible liquid to a larger piston, producing a much larger force. It is used to compress materials, make bales, or stamp designs.


  14. Explain the working of a hydraulic jack.
     Answer: A hydraulic jack is used to lift heavy vehicles. A small piston is pumped, creating pressure in the hydraulic fluid, which is transmitted to a large piston. This large piston rises, lifting the vehicle with a small applied force on the small piston.


  15. Explain the working of hydraulic brakes.
     Answer: Hydraulic brakes use incompressible brake fluid to transmit pressure. When the driver presses the brake pedal, pressure is transmitted equally through the fluid to all brakes, ensuring equal braking force on all wheels, which provides effective and safe braking.


  16. Define atmospheric pressure.
     Answer: Atmospheric pressure is the pressure exerted by the air column above the Earth’s surface due to its weight. Its standard value at sea level is 1.013 × 10⁵ Pa (1 atmosphere).


  17. Give examples of atmospheric pressure in daily life.
     Answer: Examples include: Sucking a drink through a straw, filling a syringe with liquid, filling ink into a fountain pen, action of rubber suckers, siphon systems, and removing oil from a sealed oil can.


  18. Describe the measurement of atmospheric pressure.
     Answer: Atmospheric pressure is measured using barometers. A mercury barometer shows a standard height of about 76 cm Hg at sea level and 0°C. Fortin barometers are portable and have an adjustable screw for accuracy. Aneroid barometers measure pressure without liquid and are compact and easy to read.


  19. Explain the advantages of using mercury in a barometer.
     Answer: Mercury has high density, requiring a short column; it has low vapor pressure, so it does not evaporate easily; and it does not stick to glass, providing accurate readings.


  20. Explain the disadvantages of using water in a barometer.
     Answer: Water has low density, requiring a very long column (~10.4 m), evaporates quickly, and wets glass, making readings inaccurate.


  21. Describe the Fortin barometer.
     Answer: A Fortin barometer is a portable barometer with a cistern and an adjustable screw. It allows accurate measurement of atmospheric pressure by adjusting the mercury level for precise readings.


  22. Describe an aneroid barometer.
     Answer: An aneroid barometer measures atmospheric pressure without using liquid. It is portable, compact, spill-proof, and readings can be easily observed on a dial.


  23. How does atmospheric pressure vary with altitude?
     Answer: Atmospheric pressure decreases with increase in altitude because air density decreases as we move higher above sea level.


  24. Explain how a barometer can be used to forecast weather.
     Answer: A sudden fall in barometric height indicates approaching storm or rain, while a sudden rise indicates clear and fair weather.


  25. Explain the working of an altimeter.
     Answer: An altimeter is a modified aneroid barometer used in aircraft to measure height above sea level. It measures changes in atmospheric pressure and converts them into altitude readings.


  26. Explain why a knife edge, needle, or pin produces high pressure.
     Answer: The contact area at the edge of a knife, needle, or pin is very small. For the same thrust, smaller area produces greater pressure, making it easier to cut, pierce, or penetrate surfaces.


  27. Explain why skis have narrow edges.
     Answer: Narrow edges reduce the area in contact with ice, producing greater pressure per unit area. This allows the skier to cut through ice and maintain control.


  28. Explain why school bags have broad straps.
     Answer: Broad straps increase the area of contact on shoulders, reducing pressure and making it easier and more comfortable to carry heavy bags.


  29. Explain why tractors have broad tyres.
     Answer: Broad tyres increase the area of contact with the ground, reducing pressure and preventing the tractor from sinking into soft soil.


  30. Explain hydrostatic pressure in liquids.
     Answer: Hydrostatic pressure is the pressure exerted by a liquid at rest due to the weight of the liquid above. It is given by P = h × ρ × g and acts equally in all directions.


  31. Explain why pressure at the same depth in a liquid is equal.
     Answer: At a given depth, the weight of the liquid above is the same, so the pressure exerted is identical at all points at that depth, independent of the container’s shape.


  32. Explain the consequence of liquid pressure on dams.
     Answer: Because pressure increases with depth, dams are built thicker at the bottom to resist high water pressure and maintain stability.


  33. Explain why submarines and scuba suits are designed for high pressure.
     Answer: At greater depths, liquid pressure is high. Submarine hulls are reinforced and scuba suits are specially designed to withstand this pressure, preventing damage or injury.


  34. Explain why atmospheric pressure can lift liquid in a straw.
     Answer: Atmospheric pressure outside the straw is greater than the pressure inside when we suck, pushing the liquid up into the mouth.


  35. Explain the role of atmospheric pressure in a syringe.
     Answer: Pulling the plunger decreases pressure inside the syringe; higher atmospheric pressure pushes liquid into it.


  36. Explain the working of a siphon using atmospheric pressure.
     Answer: Atmospheric pressure pushes liquid from a higher container through a tube to a lower container when the tube is filled and siphoning starts.


  37. Explain why liquid pressure depends on density.
     Answer: Higher density means more mass per unit volume, increasing the weight of liquid above a point and hence increasing pressure.


  38. Explain why liquid pressure depends on gravity.
     Answer: Greater gravitational acceleration increases the weight of the liquid column, raising the pressure at a point.


  39. Explain why pressure is independent of liquid volume.
     Answer: Pressure at a point depends on the height of the liquid column, density, and gravity, not the total volume of liquid.


  40. Explain why dams fail if incorrectly designed.
     Answer: If thickness at the bottom is insufficient, high pressure at depth may exceed structural strength, causing cracks or collapse.


  41. Explain why hydraulic machines are important in industries.
     Answer: They allow small input forces to generate large output forces, making it possible to lift heavy objects and perform industrial tasks efficiently.


  42. Explain why aneroid barometers are preferred in aircraft.
     Answer: They are compact, portable, spill-proof, and provide easy readings of atmospheric pressure for altitude measurement.


  43. Explain why mercury does not stick to glass in barometers.
     Answer: Mercury has low adhesion to glass surfaces, allowing the column to move freely and provide accurate measurements.


  44. Explain why pressure acts equally in all directions in a liquid.
     Answer: Liquid particles collide randomly and transmit applied pressure uniformly, resulting in equal pressure in all directions.


  45. Explain why pressure is greater at deeper points in liquids.
     Answer: The weight of the liquid above increases with depth, causing greater force per unit area and hence higher pressure.


  46. Explain the effect of temperature on barometric height.
     Answer: Higher temperature reduces air or mercury density, slightly affecting barometric readings.


  47. Explain why a falling barometer predicts rain.
     Answer: A sudden decrease in atmospheric pressure indicates the approach of low-pressure weather systems, causing rain or storms.


  48. Explain why a rising barometer predicts fair weather.
     Answer: An increase in atmospheric pressure indicates high-pressure systems, associated with clear skies and stable weather.


  49. Explain the principle behind hydraulic lift.
     Answer: A small force applied on a small piston is transmitted undiminished through incompressible fluid to a larger piston, lifting heavy loads.


  50. Explain why hydrostatic pressure acts in all directions.
     Answer: Liquid particles are in continuous random motion and collisions transmit pressure equally along all directions.

Give Reasons

  1. Give reason why a sharp knife cuts better than a blunt knife.
     Answer: A sharp knife has a smaller contact area, producing greater pressure for the same thrust, which makes cutting easier.


  2. Give reason why pressure decreases when area of contact is increased.
     Answer: Pressure = Thrust ÷ Area, so increasing area reduces pressure for the same thrust.


  3. Give reason why dams are thicker at the bottom.
     Answer: Pressure in a liquid increases with depth, so the bottom of the dam must be thicker to withstand higher pressure.


  4. Give reason why submarines have strong hulls.
     Answer: Submarines operate at great depths where water pressure is high, so strong hulls prevent crushing.


  5. Give reason why broad straps are used on school bags.
     Answer: Broad straps increase contact area on shoulders, reducing pressure and making carrying easier.


  6. Give reason why camels have broad feet.
     Answer: Broad feet increase contact area on sand, reducing pressure and preventing sinking.


  7. Give reason why narrow edges are used on skis.
     Answer: Narrow edges reduce area, increasing pressure to cut through ice effectively.


  8. Give reason why hydraulic machines can lift heavy loads.
     Answer: Pascal’s Law allows a small force on a small piston to be transmitted to a large piston, amplifying force.


  9. Give reason why liquids exert pressure in all directions.
     Answer: Particles in liquids are in continuous random motion, transmitting pressure equally in all directions.


  10. Give reason why pressure in a liquid depends on depth.
     Answer: Greater depth means more liquid weight above a point, producing higher pressure.


  11. Give reason why pressure in a liquid depends on density.
     Answer: Higher density increases mass of the liquid above a point, increasing weight and pressure.


  12. Give reason why pressure in a liquid depends on gravity.
     Answer: Greater gravitational acceleration increases the weight of the liquid column, raising pressure.


  13. Give reason why pressure is independent of the shape of the container.
     Answer: Pressure depends only on height of liquid column, density, and gravity, not container shape.


  14. Give reason why atmospheric pressure decreases with altitude.
     Answer: Air density decreases with height, reducing the weight of air column and thus atmospheric pressure.


  15. Give reason why a syringe fills liquid when plunger is pulled.
     Answer: Pulling the plunger reduces pressure inside, and higher atmospheric pressure pushes liquid into the syringe.


  16. Give reason why a straw allows liquid to be sucked.
     Answer: Atmospheric pressure outside the straw pushes liquid up when pressure inside is reduced by sucking.


  17. Give reason why ink flows in a fountain pen.
     Answer: Atmospheric pressure pushes ink into the nib when air pressure outside is higher than inside the pen.


  18. Give reason why mercury is used in barometers.
     Answer: Mercury has high density, low vapor pressure, and does not stick to glass, allowing accurate readings with a short column.


  19. Give reason why water is unsuitable for barometers.
     Answer: Water requires a very long column (~10.4 m), evaporates quickly, and wets glass, making readings inaccurate.


  20. Give reason why Fortin barometer is portable.
     Answer: It has a cistern and adjustable screw allowing compact and accurate pressure measurement.


  21. Give reason why aneroid barometers are used in aircraft.
     Answer: They are compact, portable, spill-proof, and provide easy readings of atmospheric pressure for altitude measurement.


  22. Give reason why hydraulic brakes apply equal force on all wheels.
     Answer: Brake fluid transmits pressure equally in all directions, ensuring uniform braking.


  23. Give reason why liquid pressure acts equally at a point.
     Answer: Random collisions of particles transmit applied pressure uniformly in all directions.


  24. Give reason why a small piston in hydraulic press produces a large force on a big piston.
     Answer: Pascal’s Law transmits pressure equally, so larger piston area multiplies force.


  25. Give reason why pressure depends on thrust.
     Answer: Pressure = Thrust ÷ Area; greater thrust produces greater force per unit area.


  26. Give reason why pressure decreases when thrust is reduced.
     Answer: Lower thrust means less force per unit area, so pressure decreases.


  27. Give reason why pressure is higher at greater depth in a liquid.
     Answer: More liquid above a point increases the weight, producing higher pressure.


  28. Give reason why submarines are built in cylindrical shapes.
     Answer: Cylindrical shapes distribute liquid pressure evenly, increasing structural strength.


  29. Give reason why hydraulic jack lifts vehicles with small effort.
     Answer: Small force on small piston is transmitted to large piston, multiplying output force.


  30. Give reason why hydraulic press is used for compressing materials.
     Answer: Pascal’s Law allows small applied force to generate large compressive force.


  31. Give reason why atmospheric pressure can lift liquid in a straw.
     Answer: Higher atmospheric pressure outside pushes liquid into low-pressure region inside straw.


  32. Give reason why sudden fall in barometer indicates storm or rain.
     Answer: Low-pressure systems cause unstable weather, leading to storm or rain.


  33. Give reason why sudden rise in barometer indicates clear weather.
     Answer: High-pressure systems indicate stable air, resulting in clear weather.


  34. Give reason why altimeter works using atmospheric pressure.
     Answer: Altimeter measures changes in air pressure with altitude and converts them into height readings.


  35. Give reason why knife edges, pins, and needles produce high pressure.
     Answer: Small contact area produces greater pressure for the same thrust, making penetration easier.


  36. Give reason why skis cut ice efficiently.
     Answer: Narrow edges concentrate force, producing high pressure to cut ice.


  37. Give reason why school bags are more comfortable with broad straps.
     Answer: Broad straps distribute weight over larger area, reducing pressure on shoulders.


  38. Give reason why tractors do not sink in fields with broad tyres.
     Answer: Broad tyres increase area of contact, reducing pressure on soft soil.


  39. Give reason why pressure at a point in liquid is independent of container volume.
     Answer: Pressure depends on height, density, and gravity, not the total volume of liquid.


  40. Give reason why hydrostatic pressure acts in all directions.
     Answer: Random motion and collisions of liquid particles transmit pressure equally in all directions.


  41. Give reason why submarines must have strong walls.
     Answer: To withstand high water pressure at great depths and prevent crushing.


  42. Give reason why liquid pressure increases with density.
     Answer: Denser liquids have more mass per unit volume, increasing weight and pressure.


  43. Give reason why pressure depends on gravitational acceleration.
     Answer: Greater g increases weight of liquid column, producing higher pressure.


  44. Give reason why dams fail if designed too thin at the bottom.
     Answer: Bottom pressure may exceed strength, causing structural failure.


  45. Give reason why a hydraulic lift is widely used in garages.
     Answer: It allows lifting of heavy vehicles with minimal effort due to force multiplication.


  46. Give reason why atmospheric pressure can remove oil from a sealed oil can.
     Answer: Air pressure outside the can pushes oil out when vacuum is created inside.


  47. Give reason why pressure in a liquid does not depend on shape of container.
     Answer: Pressure depends only on liquid height, density, and gravity, not container shape.


  48. Give reason why Fortin barometer gives accurate readings.
     Answer: Adjustable cistern allows precise leveling of mercury for exact measurement.


  49. Give reason why aneroid barometer is preferred in the field.
     Answer: It is portable, compact, and avoids liquid spillage, making it easy to use.


  50. Give reason why pressure is inversely proportional to area.
     Answer: For the same thrust, larger area spreads the force, reducing pressure per unit area.

Arrange the Words 

Case Studies

  1. Case Study: A sharp knife is used to cut vegetables while a blunt knife struggles. Explain why this happens.
     Answer: The sharp knife has a smaller contact area, so for the same thrust, it produces greater pressure, making cutting easier.


  2. Case Study: A school bag with broad straps is more comfortable to carry than one with thin straps. Explain.
     Answer: Broad straps increase the contact area on shoulders, reducing pressure and distributing the weight evenly.


  3. Case Study: Tractors have broad tyres when moving on soft fields. Why?
     Answer: Broad tyres increase the contact area with soil, reducing pressure and preventing the tractor from sinking.


  4. Case Study: A dam is constructed thicker at the base than at the top. Explain the reason.
     Answer: Pressure in water increases with depth, so a thicker base is required to withstand higher pressure at lower levels.


  5. Case Study: A hydraulic jack is used to lift a car using minimal effort. How does it work?
     Answer: Pascal’s Law transmits the small force applied on a small piston to a large piston, multiplying the output force to lift the car.


  6. Case Study: Submarines are cylindrical and have strong walls. Why is this design used?
     Answer: Cylindrical shape distributes water pressure evenly, and strong walls resist the high pressure at greater depths.


  7. Case Study: Mercury is preferred in barometers over water. Why?
     Answer: Mercury has high density (shorter column), low vapor pressure (less evaporation), and does not stick to glass, making it accurate and convenient.


  8. Case Study: A syringe fills with liquid when the plunger is pulled. Explain.
     Answer: Pulling the plunger reduces pressure inside, and higher atmospheric pressure outside pushes liquid into the syringe.


  9. Case Study: Drinking through a straw works even with a very small suction. Why?
     Answer: Atmospheric pressure outside the straw pushes liquid into the low-pressure region created by suction.


  10. Case Study: Hydraulic brakes ensure equal braking force on all wheels. How?
     Answer: Brake fluid transmits pressure equally in all directions, so each wheel receives the same braking force.


  11. Case Study: A needle penetrates the skin easily but a blunt pin does not. Explain.
     Answer: The needle has a smaller contact area, producing higher pressure for the same thrust, making penetration easier.


  12. Case Study: Fortin barometer is more accurate than a simple mercury barometer. Why?
     Answer: It has an adjustable cistern that allows precise leveling of mercury, improving measurement accuracy.


  13. Case Study: Aneroid barometers are widely used in the field. Explain the advantages.
     Answer: They are compact, portable, avoid liquid spillage, and can be read easily, making them practical for field use.


  14. Case Study: Atmospheric pressure decreases as altitude increases. Why does this happen?
     Answer: Air density decreases with altitude, reducing the weight of the air column above, hence lower pressure.


  15. Case Study: Sudden fall in barometer reading indicates rain or storm. Explain.
     Answer: Low-pressure regions cause unstable weather conditions, often leading to rain or storms.


  16. Case Study: Sudden rise in barometer reading indicates clear weather. Why?
     Answer: High-pressure regions indicate stable air and clear, calm weather.


  17. Case Study: Submarines and scuba divers require special designs to handle pressure. Why?
     Answer: At greater depths, liquid pressure is high; submarines need strong hulls, and divers use specially designed suits to withstand pressure.


  18. Case Study: A knife with the same weight can cut through ice faster if its edge is sharpened. Explain.
     Answer: Sharpening reduces contact area, increasing pressure on ice, making it easier to cut.


  19. Case Study: Altimeters in aircraft provide height above sea level. How do they function?
     Answer: They measure atmospheric pressure, which decreases with altitude, and convert the pressure readings into height.


  20. Case Study: Liquid pressure at a point inside a tank is the same in all directions. Why?
     Answer: According to hydrostatic law, liquid pressure acts equally in all directions at a given depth due to random particle motion.

Numericals

  1. A book of mass 2 kg rests on a table of area 0.5 m². Calculate the thrust and pressure exerted on the table.
     Answer:
     Thrust = Weight = m × g = 2 × 9.8 = 19.6 N
     Pressure = Thrust ÷ Area = 19.6 ÷ 0.5 = 39.2 Pa


  2. A knife applies a force of 50 N on a surface area of 0.002 m². Find the pressure exerted.
     Answer:
     Pressure = Thrust ÷ Area = 50 ÷ 0.002 = 25,000 Pa


  3. A nail has a cross-sectional area of 1 mm². A force of 100 N is applied. Calculate the pressure at the tip of the nail.
     Answer:
     Area = 1 mm² = 1 × 10⁻⁶ m²
     Pressure = 100 ÷ (1 × 10⁻⁶) = 1 × 10⁸ Pa


  4. A hydraulic press has a small piston of area 0.01 m² and large piston of area 1 m². If a force of 200 N is applied on the small piston, calculate the force on the large piston.
     Answer:
     Pascal’s Law: F₂ / A₂ = F₁ / A₁
     F₂ = F₁ × (A₂ / A₁) = 200 × (1 ÷ 0.01) = 20,000 N


  5. Water in a tank has height 5 m and density 1000 kg/m³. Calculate the pressure at the bottom. (g = 9.8 m/s²)
     Answer:
     P = h × ρ × g = 5 × 1000 × 9.8 = 49,000 Pa


  6. A diver goes 10 m below the water surface. Calculate the pressure due to water at this depth.
     Answer:
     P = h × ρ × g = 10 × 1000 × 9.8 = 98,000 Pa


  7. Atmospheric pressure at sea level is 1.013 × 10⁵ Pa. Express it in N/m².
     Answer:
     1 Pa = 1 N/m², so Pressure = 1.013 × 10⁵ N/m²


  8. A hydraulic jack has small piston area 0.02 m² and large piston area 0.5 m². Find the force required to lift a 10,000 N car.
     Answer:
     F₁ / A₁ = F₂ / A₂ → F₁ = F₂ × (A₁ / A₂) = 10,000 × (0.02 / 0.5) = 400 N


  9. A school bag of mass 10 kg has strap area 0.1 m². Calculate pressure on the shoulder.
     Answer:
     Thrust = 10 × 9.8 = 98 N
     Pressure = 98 ÷ 0.1 = 980 Pa


  10. A needle with tip area 0.5 mm² penetrates skin under a force of 50 N. Calculate pressure at tip.
     Answer:
     Area = 0.5 × 10⁻⁶ m²
     Pressure = 50 ÷ (0.5 × 10⁻⁶) = 1 × 10⁸ Pa


  11. Mercury column in a barometer is 76 cm high. Calculate pressure exerted by mercury. (ρ = 13,600 kg/m³, g = 9.8)
     Answer:
     h = 0.76 m
     P = h × ρ × g = 0.76 × 13600 × 9.8 ≈ 1.013 × 10⁵ Pa


  12. Water column height is 10.4 m in a barometer. Calculate pressure at base. (ρ = 1000 kg/m³, g = 9.8)
     Answer:
     P = 10.4 × 1000 × 9.8 = 101,920 Pa ≈ 1 atm


  13. A piston of area 0.02 m² applies 400 N force in a hydraulic press. Calculate pressure transmitted.
     Answer:
     Pressure = F / A = 400 ÷ 0.02 = 20,000 Pa


  14. A large piston of area 0.5 m² receives the pressure from above. Calculate output force. (Pressure = 20,000 Pa)
     Answer:
     F = P × A = 20,000 × 0.5 = 10,000 N


  15. Calculate the weight of 1 m³ of water. (ρ = 1000 kg/m³, g = 9.8)
     Answer:
     Weight = m × g = 1000 × 9.8 = 9,800 N


  16. Pressure exerted by 2 m of mercury. (ρ = 13,600 kg/m³)
     Answer:
     P = h × ρ × g = 2 × 13600 × 9.8 = 266,560 Pa


  17. A syringe has cross-sectional area 2 × 10⁻⁴ m². Pulling the plunger with 10 N draws liquid. Find pressure created.
     Answer:
     Pressure = F / A = 10 ÷ 2 × 10⁻⁴ = 50,000 Pa


  18. A straw has cross-sectional area 1 × 10⁻⁴ m². Suction force applied = 5 N. Find pressure reduction inside straw.
     Answer:
     Pressure = F / A = 5 ÷ 1 × 10⁻⁴ = 50,000 Pa reduction


  19. A diver experiences 3 × 10⁵ Pa pressure from water. Find depth in water. (ρ = 1000 kg/m³, g = 9.8)
     Answer:
     h = P / (ρ × g) = 3 × 10⁵ ÷ (1000 × 9.8) ≈ 30.61 m


  20. A dam is 50 m deep. Water density = 1000 kg/m³. Calculate pressure at base.
     Answer:
     P = h × ρ × g = 50 × 1000 × 9.8 = 4.9 × 10⁵ Pa


  21. A hydraulic lift has small piston 0.01 m² and large piston 0.5 m². Force on small piston = 200 N. Find force on large piston.
     Answer:
     F₂ = F₁ × (A₂ / A₁) = 200 × (0.5 / 0.01) = 10,000 N


  22. A boat floats in water. Density of water = 1000 kg/m³. Weight of boat = 5000 N. Find volume of water displaced.
     Answer:
     V = W / (ρ × g) = 5000 ÷ (1000 × 9.8) ≈ 0.510 m³


  23. A cube of side 0.2 m rests on a table. Weight = 100 N. Pressure on table?
     Answer:
     Area = 0.2² = 0.04 m²
     P = 100 ÷ 0.04 = 2500 Pa


  24. Pressure at 20 m depth in freshwater.
     Answer:
     P = 20 × 1000 × 9.8 = 196,000 Pa


  25. Pressure at 10 m depth in seawater (ρ = 1025 kg/m³).
     Answer:
     P = 10 × 1025 × 9.8 ≈ 100,450 Pa


  26. Piston area small = 0.01 m², large = 0.2 m². Input force = 100 N. Find output force.
     Answer:
     F₂ = 100 × (0.2 / 0.01) = 2000 N


  27. A needle of 0.001 m² tip area is pressed with 50 N. Pressure?
     Answer:
     P = 50 ÷ 0.001 = 50,000 Pa


  28. Atmospheric pressure = 1.013 × 10⁵ Pa. Force on 0.5 m² table?
     Answer:
     F = P × A = 1.013 × 10⁵ × 0.5 = 50,650 N


  29. Column of oil 2 m high, density 900 kg/m³. Pressure at base?
     Answer:
     P = 2 × 900 × 9.8 = 17,640 Pa


  30. Water column 3 m, pressure at bottom?
     Answer:
     P = 3 × 1000 × 9.8 = 29,400 Pa


  31. Hydraulic brake with piston 0.01 m² and pressure 2 × 10⁵ Pa. Force?
     Answer:
     F = P × A = 2 × 10⁵ × 0.01 = 2,000 N


  32. Depth = 15 m, water density 1000 kg/m³. Pressure?
     Answer:
     P = 15 × 1000 × 9.8 = 147,000 Pa


  33. Column of mercury 0.76 m, density 13,600 kg/m³. Pressure?
     Answer:
     P = 0.76 × 13,600 × 9.8 ≈ 1.013 × 10⁵ Pa


  34. Small piston area = 0.01 m², large piston area = 0.5 m². Input force = 50 N. Output force?
     Answer:
     F₂ = 50 × (0.5 / 0.01) = 2,500 N


  35. Knife exerts force of 10 N, edge area 1 × 10⁻⁴ m². Pressure?
     Answer:
     P = 10 ÷ 1 × 10⁻⁴ = 1 × 10⁵ Pa


  36. Pressure due to 0.5 m column of oil (ρ = 900 kg/m³)
     Answer:
     P = 0.5 × 900 × 9.8 = 4,410 Pa


  37. Syringe area = 2 × 10⁻⁴ m², applied force = 10 N. Pressure?
     Answer:
     P = 10 ÷ 2 × 10⁻⁴ = 50,000 Pa


  38. Water tank height = 8 m. Pressure at bottom?
     Answer:
     P = 8 × 1000 × 9.8 = 78,400 Pa


  39. Needle area = 0.5 mm², force = 40 N. Pressure?
     Answer:
     Area = 0.5 × 10⁻⁶ m²
     P = 40 ÷ (0.5 × 10⁻⁶) = 8 × 10⁷ Pa


  40. Hydraulic lift small piston area = 0.02 m², large piston area = 0.5 m², car weight = 5,000 N. Input force?
     Answer:
     F₁ = F₂ × (A₁ / A₂) = 5,000 × (0.02 / 0.5) = 200 N


  41. Pressure at 12 m depth in water.
     Answer:
     P = 12 × 1000 × 9.8 = 117,600 Pa


  42. Column of oil 4 m high, density 850 kg/m³. Pressure at base?
     Answer:
     P = 4 × 850 × 9.8 = 33,320 Pa


  43. Barometer mercury height = 0.76 m. Force on 0.1 m² area?
     Answer:
     Pressure = 1.013 × 10⁵ Pa
     F = P × A = 1.013 × 10⁵ × 0.1 = 10,130 N


  44. Knife cuts butter easily. Edge area = 2 × 10⁻⁴ m², force = 5 N. Pressure?
     Answer:
     P = 5 ÷ 2 × 10⁻⁴ = 25,000 Pa


  45. Piston small = 0.01 m², large = 0.2 m², input force = 150 N. Output force?
     Answer:
     F₂ = 150 × (0.2 / 0.01) = 3,000 N


  46. Atmospheric pressure = 1.013 × 10⁵ Pa, force on 2 m² surface?
     Answer:
     F = 1.013 × 10⁵ × 2 = 2.026 × 10⁵ N


  47. Needle tip area = 0.001 m², force = 60 N. Pressure?
     Answer:
     P = 60 ÷ 0.001 = 60,000 Pa


  48. Water column 5 m high, density = 1000 kg/m³. Pressure?
     Answer:
     P = 5 × 1000 × 9.8 = 49,000 Pa


  49. Depth = 25 m, water density = 1000 kg/m³. Pressure at bottom?
     Answer:
     P = 25 × 1000 × 9.8 = 245,000 Pa


  50. Hydraulic press small piston area = 0.02 m², large piston area = 0.5 m², input force = 100 N. Output force?
     Answer:
     F₂ = 100 × (0.5 / 0.02) = 2,500 N

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