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Class 10 Physics Chapter 10 Test 3 – Thermal Physics
Thermal Physics Chapter 10 Full unit Test 3
Prepare for the Class 10 Physics Chapter 10 Thermal Physics Test 3 with our comprehensive full-unit test designed according to the Punjab Board 2027 Model Papers and the latest syllabus issued by PECTAA Punjab. This chapter-wise test series helps students strengthen their conceptual understanding, practice important exam questions, and prepare effectively for their upcoming matric examinations. Download and practice the Class 10 Physics Thermal Physics Full Unit Test to improve your preparation and achieve better results in Punjab Board examinations.
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PHYSICSCHAPTER-10 (OBJECTIVE)CLASS TEST-3
TIME: 10 MINMARKS: 7
1. The coefficient of linear expansion of Steel is:
a) 1.9 × 10-5b) 1.7 × 10-5c) 1.2 × 10-5d) 0.9 × 10-5
Answer: (c) 1.2 × 10-5 K-1
2. What is the SI unit of specific heat capacity?
a) J·K-1b) J kg-1 K-1c) J m-3d) J s-1
Answer: (b) J kg-1 K-1
3. Formula for latent heat of fusion is:
a) Q = m × Lfb) Q = m × Lvc) Q = m × c × ΔTd) Q = P × V
Answer: (a) Q = m × Lf
4.5 High-temperature superconductors typically involve which type of material?
(a) Pure metals(b) Organic compounds(c) Ceramics(d) Liquid crystals
Answer: (c) Ceramics
5. What does a liquid turn into once it is evaporated?
(a) Gas(b) Water vapours(c) Air(d) Both (a) and (b)
Answer: (d) Both (a) and (b)
6. Mercury becomes superconducting below:
a) 7.2 Kb) 135 Kc) 4.2 Kd) 273 K
Answer: (c) 4.2 K
7. When a substance loses energy, its molecules:
a) Move fasterb) Move slowerc) Break apartd) Disappear
Answer: (b) Move slower
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PHYSICSCHAPTER-10 (SUBJECTIVE)CLASS TEST-1
TIME: 20 MINMARKS: 23
Attempt any 7 Questions.7×2=14
1. Why should we not fill a bottle of water to the top before freezing it?
Water expands (about 9%) when it freezes, so a full bottle may crack or burst.
2. If evaporation produces cooling, why does not boiling water feel cold?
Heat is supplied continuously by the burner, which is far more than the heat lost by evaporation, so the water stays hot.
3. What is thermal contraction?
The decrease in size (length, area or volume) of a substance when it is cooled.
4. Define volume thermal expansion.
The increase in volume of a substance per unit original volume per kelvin rise in temperature: β = ΔV / (V0 ΔT).
5. Define specific heat capacity.
The heat required to raise the temperature of 1 kg of a substance by 1 K. Unit: J kg-1 K-1.
6. Define evaporation.
The slow change of a liquid into vapour at its surface at any temperature below its boiling point.
7. What factors influence the thermal expansion of solids?
Original length (size), rise in temperature (ΔT) and the nature of the material (coefficient of expansion).
8. How do different materials exhibit varying thermal expansion behaviours?
Each material has its own coefficient of expansion; e.g. aluminium expands more than steel, while glass expands very little.
9. Why does a liquid evaporate faster when the air is dry?
Dry air holds little vapour, so more molecules escape and fewer return to the liquid.
10. Why do electric transmission wires sag in summer and tighten in winter?
Wires expand in summer heat (so they sag) and contract in winter cold (so they tighten).
SECTION-II (5+4)
1. How does thermal expansion differ between solids, liquids, and gases? Provide examples to illustrate these differences.(Comp.10.1)
Solids expand least (α ≈ 10-5 K-1, e.g. railway tracks), liquids expand more (e.g. mercury in a thermometer), gases expand the most (e.g. a balloon swelling in heat). The order is: solids < liquids < gases.
2. A metal rod of length 1 m expands by 0.02 m when heated from 20 °C to 120 °C. Calculate its coefficient of linear expansion.
α = ΔL / (L0 × ΔT) = 0.02 / (1 × 100) = 2 × 10-4 K-1
