FSc Part 1 Physics chapter 1: Measurements MCQs with answers

By Team Megalecture · Updated 4 Nov 2026

28 exam-style questions on Measurements, each with the answer and a short explanation. Ten of them are below to try. The chapter test draws ten fresh questions each time and is marked the moment you finish, with your score by topic.

28 questions · 3 topics · 10 per test

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What chapter 1 covers

Ten Measurements questions with answers

Try each one, then open the answer. These ten stay the same; the test draws new ones every time.

1. The speed v of a transverse wave on a string depends on the tension F and the mass per unit length μ. Dimensional analysis gives

  1. A
    v ∝ √(F/μ)
  2. B
    v ∝ F/μ
  3. C
    v ∝ √(μ/F)
  4. D
    v ∝ Fμ
Show answer

Answer: A. F/μ = [MLT−2] ÷ [ML−1] = [L2T−2], and its square root is [LT−1], a speed.

2. The wavelength of a yellow light is 550 nm. In metres, this is

  1. A
    5.5 × 10−7 m
  2. B
    5.5 × 10−9 m
  3. C
    5.5 × 10−6 m
  4. D
    5.5 × 10−10 m
Show answer

Answer: A. 1 nm = 10−9 m, so 550 nm = 550 × 10−9 m = 5.5 × 10−7 m. Writing 5.5 × 10−9 forgets to shift the decimal point.

3. With the jaws of a vernier callipers closed, the reading is +0.02 cm. When a rod is held between the jaws the reading is 2.46 cm. What is the corrected diameter of the rod?

  1. A
    2.48 cm
  2. B
    2.46 cm
  3. C
    2.44 cm
  4. D
    2.42 cm
Show answer

Answer: C. A positive zero error must be subtracted: 2.46 − 0.02 = 2.44 cm. Adding it (2.48 cm) is the usual slip.

4. The time for 20 oscillations of a pendulum is 30.0 s, measured with a stopwatch of least count 0.1 s. The time period with its uncertainty is

  1. A
    (1.50 ± 0.1) s
  2. B
    (1.500 ± 0.005) s
  3. C
    (1.5 ± 0.2) s
  4. D
    (1.500 ± 0.05) s
Show answer

Answer: B. T = 30.0/20 = 1.500 s, and the uncertainty is also divided by 20: 0.1/20 = 0.005 s. Timing many oscillations reduces the uncertainty in T.

5. The pascal (Pa), the unit of pressure, expressed in SI base units is

  1. A
    kg m−1 s−2
  2. B
    kg m s−2
  3. C
    kg m2 s−2
  4. D
    kg m−2 s−1
Show answer

Answer: A. Pa = N m−2 = (kg m s−2) ÷ m2 = kg m−1 s−2. kg m s−2 is the newton itself.

6. In the textbook sense, a measurement is more precise when it has

  1. A
    a smaller absolute uncertainty
  2. B
    a smaller percentage uncertainty
  3. C
    a value closer to the true value only by chance
  4. D
    a larger number of digits written after rounding
Show answer

Answer: A. Precision depends on the absolute uncertainty (set by the least count of the instrument). Accuracy depends on the fractional or percentage uncertainty.

7. Two lengths, 25.5 cm and 0.5 cm, are measured with the same metre rule of least count 0.1 cm. Which statement is correct?

  1. A
    both are equally precise, but 25.5 cm is more accurate
  2. B
    25.5 cm is both more precise and more accurate
  3. C
    both are equally accurate, but 0.5 cm is more precise
  4. D
    0.5 cm is more accurate because it is smaller
Show answer

Answer: A. Both have the same absolute uncertainty (0.1 cm), so they are equally precise. 0.1/25.5 is about 0.4% while 0.1/0.5 is 20%, so 25.5 cm is far more accurate.

8. Which pair of quantities has the same dimensions?

  1. A
    work and power
  2. B
    force and momentum
  3. C
    pressure and force
  4. D
    work and torque
Show answer

Answer: D. Work (F × d) and torque (r × F) are both [ML2T−2], though torque is a vector and is not measured in joules.

9. Which of these can dimensional analysis NOT do?

  1. A
    check whether an equation is homogeneous
  2. B
    find the dimensions of a derived quantity
  3. C
    find the value of a dimensionless constant such as 2π
  4. D
    suggest how a quantity depends on other quantities
Show answer

Answer: C. Pure numbers have no dimensions, so the method cannot find constants such as 2π or ½; they come from experiment or full theory.

10. In the equation x = A sin ωt, where x and A are displacements and t is time, the dimensions of ω are

  1. A
    [T]
  2. B
    [T−1]
  3. C
    [LT−1]
  4. D
    none, ω is a pure number
Show answer

Answer: B. The angle ωt must be dimensionless, so ω has dimensions [T−1]. ω itself is not dimensionless; only the product ωt is.

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Ways to practise this chapter

Measurements: questions students ask

How many Measurements MCQs are there?

28, each with the answer and a short explanation, across 3 topics: SI units, prefixes and significant figures, Errors and uncertainties, Dimensions of physical quantities. Every chapter test draws ten of them, so you can take it many times.

Is the FSc Part 1 Physics chapter 1 test free?

Yes. The test, the answers and the explanations are free and need no sign-up. Sign in only if you want your scores kept across devices.

How is the chapter test marked?

The moment you press Finish: your score, the right answer and an explanation for every question, and the ones you got wrong saved in My mistakes to retry.

Can I read the explanations in Urdu?

Yes. In practice mode and on your results you can switch the explanations to Urdu.

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