50 Physics Objective Questions on Quantities, Units, Measurements & Dimensions (With Answers and Solutions)

This set of 50 objective questions covers the core physics topics of quantities, units, measurements, and dimensions. It is designed for students preparing for JAMB, WAEC, and NABTEB examinations, as well as for educators looking for practice resources. Questions range from identifying fundamental and derived quantities, deriving SI units, performing dimensional analysis, to understanding measuring instruments and measurement errors. Detailed solutions are provided for calculation-based questions to enhance understanding.

50 JAMB, WAEC & NABTEB Biology Questions on The Mammalian Ear (Theory and Objective) With Answers

Questions

1. Which of the following is a fundamental quantity?A. Area

   B. Volume

   C. Time

   D. Density

2. The SI unit of luminous intensity is theA. Kelvin

   B. Mole

   C. Candela

   D. Ampere

3. Which of the following is NOT a fundamental quantity?A. Mass

   B. Electric current

   C. Temperature

   D. Force

4. The SI unit of amount of substance is theA. kilogram

   B. mole

   C. candela

   D. ampere

5. Which pair correctly matches a fundamental quantity with its SI unit?A. Length – kilogram

   B. Mass – metre

   C. Temperature – Kelvin

   D. Time – ampere

6. A derived quantity is one thatA. cannot be measured

   B. is independent of fundamental quantities

   C. is obtained from a combination of fundamental quantities

   D. has no SI unit

7. Which of the following is a derived quantity?A. Electric current

   B. Mass

   C. Power

   D. Length

8. The derived unit of area isA. m

   B. m²

   C. m³

   D. kgm⁻²

9. Which of the following quantities has the derived unit kgm⁻³?A. Volume

   B. Density

   C. Force

   D. Pressure

10. The derived unit of velocity isA. ms⁻²

    B. ms⁻¹

    C. kgms⁻¹

    D. m²s⁻¹

11. Acceleration has the derived unitA. ms⁻¹

    B. ms⁻²

    C. kgms⁻²

    D. ms²

12. Using the defining equation force = mass × acceleration, the derived unit of force isA. kgms⁻¹

    B. kgms⁻²

    C. kgm²s⁻²

    D. kgm⁻¹s⁻²

13. The SI unit of power, the watt, can be expressed asA. kgms⁻²

    B. kgm²s⁻³

    C. kgm²s⁻²

    D. kgm⁻¹s⁻²

14. The derived unit of pressure (Nm⁻²) is equivalent toA. kgms⁻²

    B. kgm⁻¹s⁻²

    C. kgm²s⁻²

    D. kgm⁻²s⁻¹

15. Which of the following is dimensionally equivalent to the unit of impulse?A. kgms⁻¹

    B. kgms⁻²

    C. kgm²s⁻¹

    D. Nm

16. Dimensions of a physical quantity show how it is made up in terms ofA. SI units

    B. fundamental quantities

    C. derived quantities

    D. measurement instruments

17. There are three fundamental dimensions used to describe most physical quantities. They areA. L, M, T

    B. M, K, A

    C. L, M, K

    D. T, L, A

18. The dimension of length is represented byA. M

    B. L

    C. T

    D. K

19. The dimension of mass isA. L

    B. T

    C. M

    D. A

20. Derive the dimensions of velocity.A. LT⁻¹

    B. LT⁻²

    C. MLT⁻¹

    D. ML⁻¹

21. The dimensions of acceleration areA. LT⁻¹

    B. LT⁻²

    C. MLT⁻²

    D. L²T⁻¹

22. The dimensions of force areA. MLT⁻¹

    B. MLT⁻²

    C. ML²T⁻²

    D. ML⁻¹T⁻²

23. The dimensional formula for energy (work) isA. MLT⁻¹

    B. ML²T⁻²

    C. MLT⁻²

    D. ML⁻²T⁻²

24. Which of the following has dimensions ML⁻¹T⁻²?A. Force

    B. Pressure

    C. Momentum

    D. Power

25. The dimensions of impulse areA. MLT⁻¹

    B. MLT⁻²

    C. ML²T⁻²

    D. ML⁻¹T

26. The instrument used to measure length in the laboratory that has an accuracy of 1mm or 0.1cm is theA. micrometer screw gauge

    B. vernier calipers

    C. metre rule

    D. measuring tape

27. A metre rule is graduated from 0 toA. 50 cm

    B. 100 cm (1 metre)

    C. 30 cm

    D. 200 cm

28. The smallest graduation on a typical metre rule isA. 0.01 cm

    B. 0.1 cm (1 mm)

    C. 1 cm

    D. 0.001 cm

29. Error due to parallax in measurement occurs whenA. the instrument has a zero error

    B. readings are viewed from a slanting position of the eye

    C. the object is too hot

    D. the scale is not calibrated

30. A length is measured as 51.3 ± 0.1 cm. The value 0.1 cm represents theA. actual length

    B. absolute error

    C. estimated uncertainty

    D. percentage error

31. Which measuring instrument is suitable for measuring longer lengths like a road or a piece of land?A. Metre rule

    B. Vernier calipers

    C. Measuring tape

    D. Micrometer screw gauge

32. The calipers are used in conjunction with the metre rule to measureA. internal diameter of a test tube

    B. thickness of a wire

    C. external diameter of cylindrical objects

    D. depth of a beaker

33. Frequency is defined as the number of cycles per unit time. Its derived unit isA. s

    B. s⁻¹ (hertz)

    C. ms⁻¹

    D. s²

34. Which of the following quantities is dimensionless (dimensionally independent)?A. Efficiency

    B. Momentum

    C. Power

    D. Force

35. The refractive index of a medium is dimensionless because it is the ratio of theA. speeds of light in two media

    B. sines of angles (ratio of lengths)

    C. densities of two media

    D. wavelengths of light

36. Dielectric constant (relative permittivity) is dimensionally independent because it is the ratio ofA. two masses

    B. two times

    C. two capacitances

    D. two lengths

37. Which of the following groups contains only derived quantities?A. Mass, time, length

    B. Temperature, electric current, luminous intensity

    C. Area, volume, density, force

    D. Amount of substance, temperature, time

38. The SI unit of momentum isA. kgms⁻²

    B. kgms⁻¹

    C. Ns

    D. both B and C

39. One joule (J) is equivalent toA. 1 Nm

    B. 1 kgm²s⁻²

    C. 1 watt-second

    D. all of the above

40. The product of force and time gives the quantityA. work

    B. impulse

    C. power

    D. pressure

41. The dimension of power can be written asA. MLT⁻²

    B. ML²T⁻³

    C. ML²T⁻²

    D. MLT⁻¹

42. Which of the following is a fundamental quantity?A. Torque

    B. Electric current

    C. Momentum

    D. Pressure

43. The SI unit of temperature isA. Celsius

    B. Fahrenheit

    C. Kelvin

    D. Joule

44. In the equation T = 2π√(l/g), T represents period, l length, and g acceleration due to gravity. The dimension of g isA. LT⁻¹

    B. LT⁻²

    C. L²T⁻¹

    D. MLT⁻²

45. The period T of a simple pendulum depends on length l and acceleration g. Using dimensional analysis, T is proportional toA. l/g

    B. l × g

    C. √(l/g)

    D. √(g/l)

46. An example of a human error in measurement isA. zero error

    B. backlash error

    C. parallax error

    D. calibration error

47. If a student reads the scale of a metre rule from an angle instead of directly perpendicular, the error introduced isA. random error

    B. parallax error

    C. zero error

    D. systematic error

48. Which of these physical quantities is correctly paired with its SI unit?A. Power – Js⁻¹

    B. Specific latent heat – Jkg⁻¹K⁻¹

    C. Pressure – Nm⁻¹

    D. Density – kgm³

49. The derived unit of torque is the same as that ofA. force

    B. work (energy)

    C. power

    D. impulse

50. The unit kgm²s⁻² is equivalent toA. watt

    B. newton

    C. joule

    D. pascal

Answer Key

1. C
2. C
3. D
4. B
5. C
6. C
7. C
8. B
9. B
10. B
11. B
12. B
13. B
14. B
15. A
16. B
17. A
18. B
19. C
20. A
21. B
22. B
23. B
24. B
25. A
26. C
27. B
28. B
29. B
30. C
31. C
32. C
33. B
34. A
35. B
36. C
37. C
38. D
39. D
40. B
41. B
42. B
43. C
44. B
45. C
46. C
47. A
48. B
49. B
50. C

Solutions to Selected Questions

Q12: Force = mass × acceleration. Unit of mass = kg, unit of acceleration = ms⁻². So unit of force = kg × ms⁻² = kgms⁻² (Newton, N). Answer B.

Q13: Power = work/time = force × distance/time = (kgms⁻² × m)/s = kgm²s⁻³. Answer B.

Q14: Pressure = force/area. Unit of force = kgms⁻², area = m². So pressure unit = kgms⁻² / m² = kgm⁻¹s⁻². This is also called the Pascal (Pa). Answer B.

Q15: Impulse = force × time. Unit of force is kgms⁻², multiplied by time (s) gives kgms⁻¹. Also equivalent to Ns. Answer A.

Q20: Velocity = displacement/time. Dimension of displacement = L, time = T. Therefore dimension of velocity = L/T = LT⁻¹. Answer A.

Q22: Force = mass × acceleration. Dimension of mass = M, acceleration = LT⁻². So force = M × LT⁻² = MLT⁻². Answer B.

Q23: Work = force × distance. Dimension of force = MLT⁻², distance = L. Therefore work = MLT⁻² × L = ML²T⁻². Answer B.

Q24: Pressure = force/area = MLT⁻² / L² = ML⁻¹T⁻². Answer B.

Q25: Impulse = force × time = MLT⁻² × T = MLT⁻¹. Answer A.

Q34: Efficiency = (useful work output / total work input) × 100%. The dimensions of work cancel out, so efficiency is dimensionless. Answer A.

Q35: Refractive index n = sin i / sin r. Sine is a ratio of two lengths (opposite/hypotenuse), so the dimensions cancel, making it dimensionless. Answer B.

Q36: Dielectric constant = C_d / C_v (ratio of capacitances), thus dimensionless. Answer C.

Q42: Power = work/time. Dimension of work = ML²T⁻², time = T. Power = ML²T⁻² / T = ML²T⁻³. Answer B.

Q46: T = k lˣ gʸ. Dimensions: T = Lˣ (LT⁻²)ʸ = Lˣ⁺ʸ T⁻²ʸ. Equating powers: for L: x+y=0; for T: -2y=1 => y=-1/2, x=1/2. So T ∝ l^(1/2) g^(-1/2) = √(l/g). Answer C.

Q50: Work (energy) = force × distance = kgms⁻² × m = kgm²s⁻² (joule). Answer C.