JEE (Main) · Physics, Class 11
Physical World and Measurement: JEE Main PYQ, 2020–2025
Physical World and Measurement (Physics, Class 11) has been asked 127 times in the 111 JEE (Main) shift papers from 2020–2025: about 1.1 questions a paper, 4% of all Physics questions. It is the 14th most-asked of 20 Physics chapters. The 2025 shifts had 24 from it in all. Last checked 28 October 2026.
Questions per year, all shifts
Year by year.
| Year | Questions |
|---|---|
| 2020 | 14in 14 papers |
| 2021 | 26in 26 papers |
| 2022 | 26in 24 papers |
| 2023 | 12in 12 papers |
| 2024 | 25in 18 papers |
| 2025 | 24in 17 papers |
JEE (Main) is sat in many shifts a year, each with its own paper; the counts add up every shift. 2021–2024 papers had 30 questions a subject, the others 25.
Inside the chapter
Topics asked most.
- Dimensional analysis60
- Error analysis38
- Units and dimensions23
- Significant figures6
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10 Physical World and Measurement questions to practise.
Our own questions, written in the JEE Main pattern and checked, each with an explanation. Pick an option to see the answer.
Q1 · Physics · Physical World and Measurement
A length is recorded as 2.50 m. When the same length is expressed in centimetres, how many significant figures does the value have?
Answer: (B)
Principle: significant figures are a property of the measured value, and unit conversion by an exact factor does not change them. 2.50 m has three significant figures. Multiplying by the exact factor 100 cm/m gives 250 cm, which must be written as 2.50 × 10² cm to show that three figures are still significant. Writing it as 250 cm would look like two significant figures, which is the usual error.
Q2 · Physics · Physical World and Measurement
Three samples of masses 12.11 g, 3.4 g and 0.652 g are put together in a dish. To the appropriate number of significant figures, the total mass should be reported as:
Answer: (C)
In addition or subtraction the result keeps as many decimal places as the term with the fewest decimal places. The sum is 16.162 g, and 3.4 g has only one decimal place, so the total is reported as 16.2 g.
Q3 · Physics · Physical World and Measurement
The length of a wire is measured as (80.0 ± 0.1) cm before loading and (80.5 ± 0.1) cm after loading. What is the maximum percentage error in the extension of the wire?
Answer: (C)
The extension is 80.5 − 80.0 = 0.5 cm and its absolute error is 0.1 + 0.1 = 0.2 cm, since absolute errors add in a difference. The percentage error is (0.2/0.5) × 100 = 40 %: a small difference of two nearly equal readings is very uncertain.
Q4 · Physics · Physical World and Measurement
A resistance is found from R = V/I, with V = (100 ± 5) V and I = (10 ± 0.2) A. What is the maximum percentage error in R?
Answer: (D)
ΔR/R = ΔV/V + ΔI/I = 5/100 + 0.2/10 = 0.05 + 0.02 = 0.07, a maximum error of 7%.
Q5 · Physics · Physical World and Measurement
A metal piece has a mass of 8.50 g and a volume of 3.2 cm³. Its density, reported with the correct number of significant figures, is:
Answer: (D)
For multiplication and division the result has as many significant figures as the least precise quantity. The mass 8.50 g has three significant figures and the volume 3.2 cm³ has two. The calculation gives 8.50 / 3.2 = 2.65625 g cm⁻³, which is rounded to two significant figures as 2.7 g cm⁻³.
Q6 · Physics · Physical World and Measurement
The radius R of the shock front of a strong explosion is assumed to depend only on the energy E released, the time t elapsed since the explosion, and the density ρ of the surrounding air, as R ∝ Eᵃ tᵇ ρᶜ. At the same instant t and in air of the same density, the energy released is increased 32 times. By what factor does R increase?
Answer: (C)
Write the dimensions as [L] = [M L² T⁻²]ᵃ [T]ᵇ [M L⁻³]ᶜ. Mass: a + c = 0. Length: 2a − 3c = 1. Time: −2a + b = 0. From the mass equation c = −a, so the length equation gives 2a + 3a = 1, hence a = 1/5, c = −1/5 and b = 2/5. So R ∝ E^(1/5) t^(2/5) ρ^(−1/5). With t and ρ fixed, R ∝ E^(1/5). Multiplying E by 32 multiplies R by 32^(1/5) = 2.
Q7 · Physics · Physical World and Measurement
Young's modulus of a material is defined as the ratio of stress to strain. What is the dimensional formula of Young's modulus?
Answer: (A)
Principle: a ratio of two quantities has the dimensions of the numerator divided by the denominator. Stress = Force/Area has dimensions [M L T⁻²]/[L²] = [M L⁻¹ T⁻²]. Strain = change in length/original length is a pure ratio of lengths, so it is dimensionless. Young's modulus = stress/strain therefore has dimensions [M L⁻¹ T⁻²], the same as stress.
Q8 · Physics · Physical World and Measurement
The speed v of short surface ripples on a liquid is assumed to depend only on the surface tension S of the liquid (dimensions of force per unit length), the density ρ of the liquid, and the wavelength λ of the ripples. Using dimensional analysis, which expression for v is dimensionally consistent (the numerical constant is dimensionless)?
Answer: (B)
Write v = k Sᵃ ρᵇ λᶜ. The dimensions are [v] = L T⁻¹, [S] = M T⁻², [ρ] = M L⁻³ and [λ] = L. Equating powers of M gives a + b = 0. Equating powers of T gives −2a = −1, so a = 1/2 and b = −1/2. Equating powers of L gives −3b + c = 1, so 3/2 + c = 1 and c = −1/2. Hence v ∝ S^(1/2) ρ^(−1/2) λ^(−1/2) = √(S/(ρλ)).
Q9 · Physics · Physical World and Measurement
A vernier callipers has 10 vernier scale divisions equal to 9 main scale divisions, and 1 main scale division is 1 mm. With the jaws closed, the 5th vernier division coincides with a main scale division and the zero of the vernier lies to the right of the main scale zero. A wire is then placed between the jaws. The main scale reads 0.3 cm and the 8th vernier division coincides with a main scale division. Taking the error in the corrected diameter as one least count of the instrument, what is the percentage error in the cross-sectional area (A = πd²/4) of the wire?
Answer: (A)
Least count = 1 MSD − 1 VSD = 1 mm − 0.9 mm = 0.1 mm = 0.01 cm. The zero error is positive: 5 × 0.01 = +0.05 cm, so it is subtracted. The reading is 0.3 + 8 × 0.01 = 0.38 cm, and the corrected diameter is 0.38 − 0.05 = 0.33 cm. Since A ∝ d², ΔA/A = 2Δd/d = 2 × 0.01/0.33 ≈ 0.061, which is 6.1%.
Q10 · Physics · Physical World and Measurement
Which of the following pairs of quantities have the same dimensions?
Answer: (D)
Work is force × displacement and torque is force × perpendicular distance, so both are [M L² T⁻²], though torque is not measured in joules.
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All 127 real JEE Main questions from Physical World and Measurement.
The questions from the actual papers, with the official answer and an explanation for each — chapter by chapter, or as full timed papers.
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About Physical World and Measurement in JEE Main.
How many questions come from Physical World and Measurement in JEE Main?
Physical World and Measurement (Physics, Class 11) has been asked 127 times in the 111 JEE (Main) shift papers from 2020–2025: about 1.1 questions a paper, 4% of all Physics questions. It is the 14th most-asked of 20 Physics chapters. The 2025 shifts had 24 from it in all.
Which topics of Physical World and Measurement are asked most in JEE Main?
Dimensional analysis (60), Error analysis (38), Units and dimensions (23), Significant figures (6), counted over the papers from 2020–2025.
Is Physical World and Measurement important for JEE Main 2027?
It is in the syllabus in force, so it can be asked. By past papers it ranks 14 of 20 in Physics; use that to decide how much time it gets, not whether to study it.
Where can I solve Physical World and Measurement JEE Main previous year questions?
On Nikaalle, free: sign up and practise every past JEE Main question from Physical World and Measurement with an explanation for each, or sit the full papers timed. The ten questions on this page are our own, written in the same pattern.
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