ICSE – Grade 10 – Physics – Ch 01 – QA

Each question includes:

• Assertion (A)
• Reason (R)
• Correct Answer on the next line (choose from A, B, C, or D)
  • A: Both A and R are true, and R is the correct explanation of A.
  • B: Both A and R are true, but R is not the correct explanation of A.
  • C: A is true, but R is false.
  • D: A is false, but R is true.

1. A: Moment of force causes rotational motion.
    R: Moment is the product of force and perpendicular distance from pivot.
    A
   
   
   
2. A: SI unit of moment of force is newton.
    R: Moment of force is a type of force.
    D
   
   
   
3. A: A longer spanner is more effective than a shorter one.
    R: Moment of force increases with increase in perpendicular distance.
    A
   
   
   
4. A: A force always produces rotation in a body.
    R: Torque is the turning effect of a force.
    C
   
   
   
5. A: A seesaw works on the principle of moments.
    R: When clockwise moment equals anticlockwise moment, body is in equilibrium.
    A
   
   
   
6. A: Translational equilibrium exists when net force acting is zero.
    R: A body can accelerate under translational equilibrium.
    C
   
   
   
7. A: The direction of moment depends on the direction of force.
    R: Moment is a scalar quantity.
    C
   
   
   
8. A: Centripetal force is required for uniform circular motion.
    R: It acts away from the centre of the circular path.
    C
   
   
   
9. A: Centrifugal force is a real force.
    R: It acts away from the centre in circular motion.
    D
   
   
   
10. A: Torque and moment refer to the same physical quantity.
     R: Both are vector quantities representing rotational effect.
     A
    
    
    
11. A: The centre of gravity of a uniform rod lies at its midpoint.
     R: The mass is evenly distributed in a uniform rod.
     A
    
    
    
12. A: Centre of gravity may lie outside the object.
     R: The location of CG depends on the shape of the object.
     A
    
    
    
13. A: In an irregular lamina, the CG is found by balancing it on a knife edge.
     R: The CG is where the lamina balances in any suspended position.
     B
    
    
    
14. A: Moment of force is maximum when force acts perpendicular to the line joining the pivot.
     R: Torque is directly proportional to sine of angle between force and position vector.
     A
    
    
    
15. A: A fan blade exhibits translational motion.
     R: In rotational motion, all particles move same distance in same time.
     D
    
    
    
16. A: Frictional force can act as centripetal force in circular motion.
     R: On a flat road, friction provides necessary centripetal force to vehicles.
     A
    
    
    
17. A: Torque is a scalar quantity.
     R: It depends only on the magnitude of force and distance.
     C
    
    
    
18. A: In uniform circular motion, speed is constant but velocity changes.
     R: The direction of motion continuously changes.
     A
    
    
    
19. A: A body in equilibrium always remains at rest.
     R: Net force and net torque acting on it are zero.
     C
    
    
    
20. A: In the CG method, plumb lines intersect at the CG of lamina.
     R: Plumb line always hangs vertically under gravity.
     A
    
    
    
21. A: Seesaw is balanced when heavier child sits farther from the pivot.
     R: Moment depends on both weight and distance.
     A
    
    
    
22. A: A stone tied to a string and whirled in circle moves in straight line when string breaks.
     R: A body continues in its state of motion unless acted upon by external force.
     A
    
    
    
23. A: Torque is measured in joules.
     R: Torque is a form of energy.
     D
    
    
    
24. A: A spanner requires more force when its handle is shortened.
     R: Reducing perpendicular distance reduces the moment for same force.
     A
    
    
    
25. A: Direction of torque is determined using right-hand rule.
     R: Torque is a vector quantity.
     A
    
    
    
26. A: In rotational equilibrium, net force must be zero.
     R: A body not moving linearly must have zero force.
     C
    
    
    
27. A: Torque can be zero even if force is applied.
     R: Moment arm may be zero.
     A
    
    
    
28. A: Lever and pulley work on Newton’s laws.
     R: Both apply the principle of moment.
     B
    
    
    
29. A: Uniform circular motion is non-accelerated motion.
     R: Velocity remains constant.
     D
    
    
    
30. A: The greater the perpendicular distance, the greater the moment for same force.
     R: Moment is inversely proportional to distance.
     C
    
    
    
31. A: The force of gravity can act as centripetal force.
     R: Planets revolve around the Sun due to gravitational force.
     A
    
    
    
32. A: Friction acts opposite to direction of motion.
     R: Friction is a non-contact force.
     C
    
    
    
33. A: Force × distance = work.
     R: Force × perpendicular distance = moment.
     B
    
    
    
34. A: A metre rule balances when moments are unequal.
     R: Balance occurs only when clockwise moment = anticlockwise moment.
     D
    
    
    
35. A: Torque causes linear motion.
     R: It results from applying force at a distance.
     C
    
    
    
36. A: A rigid body can only undergo translational motion.
     R: Rigid body cannot rotate.
     D
    
    
    
37. A: The CG of a body is always inside the object.
     R: CG depends only on mass.
     D
    
    
    
38. A: The longer the lever arm, the less force required to rotate.
     R: Moment increases with distance from pivot.
     A
    
    
    
39. A: In circular motion, centripetal acceleration acts along the tangent.
     R: Tangent represents velocity direction.
     C
    
    
    
40. A: Moment and work have same units.
     R: Both involve product of force and displacement.
     B
    
    
    
41. A: The direction of friction is same as motion.
     R: Friction opposes motion.
     C
    
    
    
42. A: Force can act without producing moment.
     R: Moment depends on point of application and direction.
     A
    
    
    
43. A: Inertia is the cause of centrifugal force.
     R: Body resists change in its straight-line motion.
     A
    
    
    
44. A: A spinning fan shows translational motion.
     R: Blades move around an axis.
     C
    
    
    
45. A: Torque has magnitude and direction.
     R: It is a vector quantity.
     A
    
    
    
46. A: When the net moment is zero, a body is definitely at rest.
     R: Zero moment implies zero linear velocity.
     C
    
    
    
47. A: A lever of the third order has load in the middle.
     R: In all levers, load lies between effort and fulcrum.
     C
    
    
    
48. A: A body moving in a circle is acted upon by a real outward force.
     R: The centrifugal force is real and measurable.
     D
    
    
    
49. A: Rotational motion involves a fixed axis.
     R: All particles move in circular path around axis.
     A
    
    
    
50. A: Centre of gravity and centre of mass are always same.
     R: Weight and mass always act at same point.
     C