PHYSICS FORM ONE – 50 QUESTIONS AND ANSWERS

SECTION A: SHORT ANSWER QUESTIONS

1. What is Physics?
   Answer: Physics is the branch of science that deals with matter, energy, motion and their interactions.

2. Mention four branches of Physics.
   Answer: Mechanics, heat, optics and electricity.

3. What is measurement?
   Answer: Measurement is the process of determining the magnitude of a physical quantity using a suitable unit.

4. What is a physical quantity?
   Answer: A physical quantity is a quantity that can be measured and expressed using a numerical value and a unit.

5. Mention four fundamental physical quantities.
   Answer: Length, mass, time and temperature.

6. What is the SI unit of length?
   Answer: Metre (m).

7. What is the SI unit of mass?
   Answer: Kilogram (kg).

8. What is the SI unit of time?
   Answer: Second (s).

9. What is the SI unit of temperature?
   Answer: Kelvin (K).

10. What instrument is used to measure length?
    Answer: Metre rule or measuring tape.

11. What instrument is used to measure mass?
    Answer: Beam balance or electronic balance.

12. What instrument is used to measure temperature?
    Answer: Thermometer.

13. What is a force?
    Answer: A force is a push or pull that can change the state of motion or shape of an object.

14. What is the SI unit of force?
    Answer: Newton (N).

15. Name two effects of force.
    Answer: Force can change the motion of an object and can change its shape.

16. What is density?
    Answer: Density is the mass per unit volume of a substance.

17. State the formula for density.
    Answer: Density = Mass ÷ Volume.

18. What is relative density?
    Answer: Relative density is the ratio of the density of a substance to the density of water for liquids and solids.

19. What is pressure?
    Answer: Pressure is the force acting normally per unit area.

20. State the formula for pressure.
    Answer: Pressure = Force ÷ Area.

21. What is surface tension?
    Answer: Surface tension is the tendency of the surface of a liquid to behave like a stretched elastic membrane.

22. What is a micrometer screw gauge?
    Answer: A micrometer screw gauge is an instrument used to measure very small dimensions accurately.

23. What is meant by sinking?
    Answer: Sinking occurs when an object moves downward through a liquid because its average density is greater than that of the liquid.

24. What is meant by floating?
    Answer: Floating occurs when an object remains on the surface of a liquid because the upward buoyant force balances its weight.

25. Mention two mechanical properties of matter.
    Answer: Elasticity and plasticity.

SECTION B: COMPETENCE-BASED QUESTIONS

26. A student wants to measure the length of a classroom. Which instrument would be suitable?
    Answer: A measuring tape would be suitable because it can measure relatively long distances.

27. A student measures a book and obtains 25 cm. Express this measurement in metres.
    Answer: 25 cm = 0.25 m.

28. A student wants to measure the diameter of a thin wire accurately. Which instrument should be used?
    Answer: A micrometer screw gauge.

29. A shopkeeper wants to determine the mass of a bag of rice. Which instrument should be used?
    Answer: A weighing balance.

30. A metal block has a mass of 200 g and a volume of 50 cm³. Calculate its density.
    Answer: Density = Mass ÷ Volume = 200 ÷ 50 = 4 g/cm³.

31. A student pushes a stationary desk but it does not move. Give one possible reason.
    Answer: The applied force may be insufficient to overcome the frictional force opposing the motion.

32. A person carries a heavy bag using a narrow strap and feels discomfort on the shoulder. Explain why.
    Answer: The narrow strap produces greater pressure because the force acts over a smaller area.

33. Why are school bags designed with wide shoulder straps?
    Answer: Wide straps increase the area over which the weight acts, thereby reducing pressure on the shoulders.

34. A sharp knife cuts an object more easily than a blunt knife. Explain why.
    Answer: The sharp edge has a smaller area, producing greater pressure for the same applied force.

35. A student places a stone in water and it sinks. What does this indicate about the density of the stone?
    Answer: The density of the stone is greater than the density of water.

36. A piece of wood floats on water. What can be concluded about its average density?
    Answer: Its average density is less than the density of water.

37. Why does a small needle sometimes float on the surface of water when placed carefully?
    Answer: Surface tension supports the needle and prevents the water surface from breaking easily.

38. A student stretches a rubber band and then releases it. It returns close to its original shape. Which property does this demonstrate?
    Answer: Elasticity.

39. A piece of clay is pressed and remains in its new shape. Which mechanical property does this demonstrate?
    Answer: Plasticity.

40. A farmer wants to transport heavy goods using a broad platform rather than a narrow one. Explain the advantage in terms of pressure.
    Answer: A broad platform distributes the load over a larger area, reducing pressure.

41. A brick is placed on sand first on its broad face and then on its narrow face. Which position produces greater pressure on the sand?
    Answer: The narrow face produces greater pressure because the same weight acts over a smaller area.

42. A student uses a metre rule to measure the length of a table. Mention one precaution that should be taken.
    Answer: The eye should be positioned directly above the scale to avoid parallax error.

43. Why should the zero error of a measuring instrument be considered?
    Answer: It can cause an incorrect measurement if it is not identified and corrected.

44. A student wants to determine the volume of an irregular stone. Which method can be used?
    Answer: The water displacement method using a measuring cylinder can be used.

45. A stone has a mass of 300 g. When placed in a measuring cylinder, the water level rises from 50 cm³ to 100 cm³. Calculate its density.
    Answer: Volume of stone = 100 − 50 = 50 cm³.
    Density = 300 ÷ 50 = 6 g/cm³.

46. Why can a large steel ship float on water even though steel is denser than water?
    Answer: The hollow shape of the ship allows it to displace enough water so that the buoyant force can support its weight.

47. A student applies the same force to two surfaces, one small and one large. Which surface experiences greater pressure?
    Answer: The smaller surface experiences greater pressure.

48. A liquid is poured into a container. At which part of the liquid is pressure generally greater: near the surface or deeper down?
    Answer: Pressure is greater deeper down because liquid pressure increases with depth.

49. A student wants to investigate how pressure depends on area. Suggest a simple experiment.
    Answer: Place the same load on surfaces with different contact areas, such as a block placed on different faces, and compare the pressure or effect produced.

50. A student obtains different measurements when measuring the same object several times. Give two possible reasons.
    Answer: The differences may be caused by parallax error, zero error, inaccurate reading of the scale, or improper positioning of the instrument.