Prepare for your matric examinations with Class 10 Physics Chapter 10 Thermal Physics Test 4, a comprehensive Full Unit Test designed according to the latest syllabus issued by PECTAA Punjab. This chapter-wise assessment is part of the Punjab Board 2027 Physics Model Papers and helps students evaluate their understanding of Thermal Physics through exam-oriented practice. Practice important questions, strengthen physics concepts, and improve your preparation for the Class 10 Annual Board Examinations 2027 with our chapter-wise test series.
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PHYSICSCHAPTER-10 (OBJECTIVE)CLASS TEST-4
TIME: 10 MINMARKS: 7
1. What is the specific heat capacity of water?
a) 810 J kg-1 K-1b) 1,700 J kg-1 K-1c) 4,200 J kg-1 K-1d) 2,500 J kg-1 K-1
Answer: (c) 4,200 J kg-1 K-1
2. Increasing temperature makes evaporation:
a) Slowerb) Fasterc) Stopd) Unchanged
Answer: (b) Faster
3. Latent heat of fusion of ice is:
a) 2.26 × 106 J/kgb) 3.36 × 105 J/kgc) 100 J/kgd) 0 J/kg
Answer: (b) 3.36 × 105 J/kg
4. Superconductors are used in MRI machines to produce:
a) Heatb) Lightc) Strong magnetic fieldsd) Sound waves
Answer: (c) Strong magnetic fields
5. When the temperature of a rod of copper is increased, its length:
(a) remains the same(b) increases(c) decreases(d) becomes double
Answer: (b) increases
6. The amount by which unit length of a material increases when the temperature is raised to 1 °C, is called the coefficient of:
(a) cubic expansion(b) volume expansion(c) Linear expansion(d) none of these
Answer: (c) Linear expansion
7. Which property determines how much heat a solid can absorb before its temperature changes significantly?
(a) Density(b) Specific heat capacity(c) Colour(d) Hardness
Answer: (b) Specific heat capacity
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PHYSICSCHAPTER-10 (SUBJECTIVE)CLASS TEST-4
TIME: 20 MINMARKS: 23
Attempt any 7 Questions.7×2=14
1. How is heat related to our daily life?
Heat is used in cooking, heating rooms, ironing, drying clothes and running engines; it also decides weather and our comfort.
2. What is thermal expansion of gas?
The increase in volume of a gas when it is heated at constant pressure. Gases expand more than solids and liquids.
3. Define specific heat capacity of liquids.
The heat required to raise the temperature of 1 kg of a liquid by 1 K. For water it is 4,200 J kg-1 K-1.
4. How does temperature affect evaporation?
Higher temperature gives molecules more kinetic energy, so more of them escape from the surface and evaporation becomes faster.
5. Why do not train tracks buckle in winter but do in summer even though the metal is the same?(Brain.1)
In summer the rails expand and, if no gaps are left, they bend (buckle). In winter they contract, so the gaps widen and there is no pressure to buckle.
6. What is our body’s natural way of managing temperature?(T.2)
Sweating (perspiration): evaporation of sweat takes heat from the body and cools it.
7. What is latent heat of fusion?
The heat required to change 1 kg of a solid into liquid at its melting point without any change in temperature: Q = m × Lf.
8. How does evaporation contribute to cooling processes in everyday life?
Fast molecules leave the liquid and take heat with them, so the rest cools. Examples: sweating, water kept in an earthen pot, wet cloth on the forehead.
9. What is latent heat of vaporization, and how is it calculated?
The heat required to change 1 kg of a liquid into vapour at its boiling point without a change in temperature. Q = m × Lv (for water Lv = 2.26 × 106 J/kg).
10. If two liquids are heated under same conditions, but one of them heats up faster, what does this indicate about the specific heat capacity?
The liquid that heats up faster has the lower specific heat capacity, since it needs less heat for the same temperature rise.
SECTION-II (5+4)
1. Why do solids, liquids, and gases expand when heated? Explain with examples.(Comp.10.3)
Heating increases the kinetic energy of the molecules, so they vibrate or move more and the average distance between them grows. Solids: railway tracks have expansion gaps. Liquids: mercury rises in a thermometer. Gases: a balloon swells in heat. Gases expand most, solids least.
2. A steel rod initially measures 2 m at 20 °C. If its coefficient of linear expansion is 1.2×10-5 °C-1, what will be its length at 100 °C?
ΔT = 100 − 20 = 80 °C
ΔL = α L0 ΔT = 1.2×10-5 × 2 × 80 = 1.92×10-3 m
L = L0 + ΔL = 2 + 0.00192 = 2.00192 m (≈ 2.002 m)
ΔL = α L0 ΔT = 1.2×10-5 × 2 × 80 = 1.92×10-3 m
L = L0 + ΔL = 2 + 0.00192 = 2.00192 m (≈ 2.002 m)
