Prepare for your matric examinations with Class 10 Physics Chapter 10 Thermal Physics Test 5, 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 Model Papers and Test Series, helping students revise important concepts, strengthen their understanding of Thermal Physics, and practice examination-oriented questions. Attempt this Class 10 Physics full chapter test to evaluate your preparation and improve your performance in the 2027 Punjab Board examinations.
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Full Chapter Test
T-5
CHAPTER # 10
Time:15 mint(Objective Type)Total Marks: 12
| 1 | A | B | C | D |
| 2 | A | B | C | D |
| 3 | A | B | C | D |
| 4 | A | B | C | D |
| 5 | A | B | C | D |
| 6 | A | B | C | D |
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| 8 | A | B | C | D |
| 9 | A | B | C | D |
| 10 | A | B | C | D |
| 11 | A | B | C | D |
| 12 | A | B | C | D |
Note:Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fillthat circle in front of that question with Marker or Pen ink. Cutting or filling two or more circles will result in zero mark in that question.
1.
A refrigerator works based on the principles of:
(a) Nuclear physics(b) Optics(c) Mechanics(d) Thermal physics
Answer: (d) Thermal physics
2.
Which substance requires more energy to heat?
(a) Alcohol(b) Mercury(c) Copper(d) Water
Answer: (d) Water (highest specific heat capacity)
3.
The rate of evaporation increases when:
(a) Humidity increases(b) Temperature decreases(c) Wind speed increases(d) The liquid is in a tall, narrow container
Answer: (c) Wind speed increases
4.
The amount of heat required to melt 600 g of ice at 0°C is?
(a) 50 kJ(b) 201.6 kJ(c) 200 kJ(d) 150 kJ
Answer: (b) 201.6 kJ [Q = m × Lf = 0.6 × 3.36×105 = 2.016×105 J]
5.
Latent heat of fusion refers to the change from:
(a) Gas to liquid(b) Solid to liquid(c) Solid to gas(d) Liquid to gas
Answer: (b) Solid to liquid
6.
Which of the following is not a use of superconductor?
(a) MRI machines(b) Maglev trains(c) Internal combustion engines(d) Particle accelerators
Answer: (c) Internal combustion engines
7.
Which material becomes super conductor below 7.2 K?
(a) Lead(b) Mercury(c) High-temperature superconductors(d) Aluminum
Answer: (a) Lead (mercury becomes superconducting below 4.2 K)
8.
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
9.
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
10.
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)
11.
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
12.
High-temperature superconductors typically involve which type of material?
(a) Pure metals(b) Organic compounds(c) Ceramics(d) Liquid crystals
Answer: (c) Ceramics
Here is the Subjective Part of
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Marks: 48
(SUBJECTIVE TYPE)
Time: 1:45 minute
2.Write short answers to any Five (5) questions:[5×2=10]
(i)Define thermal physics.
The branch of physics that deals with heat, temperature and their relation to energy and matter.
(ii)What is thermal expansion?
The increase in the size (length, area or volume) of a substance when it is heated.
(iii)Why do liquids expand more freely than solids?
Intermolecular forces in liquids are weaker than in solids, so molecules can move apart more easily on heating.
(iv)What is real expansion of a liquid?
The actual increase in volume of a liquid on heating. Real expansion = apparent expansion + expansion of the container.
(v)Define specific heat capacity.
The heat required to raise the temperature of 1 kg of a substance by 1 K (1 °C). Unit: J kg-1 K-1.
(vi)Why do coastal areas have milder climates?
Water has a high specific heat capacity, so the sea heats and cools slowly. It keeps day/night and summer/winter temperature differences small.
(vii)Explain specific heat capacity of liquids.
Liquids, especially water (4200 J kg-1 K-1), need a large amount of heat for a small temperature change. Q = mcΔT.
(viii)How does energy absorption lead to a change in the state of matter?
Absorbed energy increases molecular kinetic energy and weakens the bonds between molecules, so a solid melts into a liquid and a liquid vaporizes into gas.
3.Write short answers to any Five (5) questions:[5×2=10]
(i)Why do materials expand on heating?
Heating increases the vibrations of particles, so the average distance between them increases.
(ii)What is thermal contraction?
The decrease in size of a substance when it is cooled.
(iii)Define linear thermal expansion.
The increase in length of a solid on heating: ΔL = αL0ΔT, where α is the coefficient of linear expansion.
(iv)What is volume thermal expansion?
The increase in volume of a substance on heating: ΔV = βV0ΔT, where β is the coefficient of volume expansion.
(v)What happens to gas in a rigid container when heated?
Its volume cannot change, so its pressure increases as the molecules move faster and hit the walls harder.
(vi)Why can gas cylinders explode in heat?
Heat raises the pressure of the gas inside the rigid cylinder. If it exceeds the cylinder’s strength, it bursts.
(vii)Why do not train tracks buckle in winter but do in summer even though the metal is the same?
In summer the rails expand and push against each other, so they buckle if there is no gap. In winter they contract, which only widens the gaps.
(viii)Why do metals heat up quickly.
Metals have free electrons and low specific heat capacity, so they conduct heat fast and warm up quickly.
4.Write short answers to any Five (5) questions:[5×2=10]
(i)How does energy loss lead to a change in the state of matter?
Losing energy slows the molecules and bonds strengthen, so a gas condenses to a liquid and a liquid freezes to a solid.
(ii)Define evaporation.
The slow change of a liquid into vapour at its surface at any temperature below its boiling point.
(iii)How does humidity affect evaporation?
High humidity slows evaporation because the air already holds much vapour. Low humidity speeds it up.
(iv)What is latent heat of vaporization?
The heat needed to change 1 kg of liquid into vapour at its boiling point without a change in temperature. Q = mLv. For water, Lv = 2.26×106 J kg-1.
(v)How does the latent heat of vaporization affect the boiling process of a liquid?
Heat supplied at boiling goes into breaking molecular bonds rather than raising the temperature. The temperature stays constant, and a large latent heat means boiling needs more energy.
(vi)What is superconductivity?
The property of certain materials to lose all electrical resistance below a critical temperature.
(vii)Name two materials that exhibit superconductivity and their critical temperatures.
Mercury: 4.2 K (−269 °C). Lead: 7.2 K (−266 °C). Niobium: 9.2 K may also be given.
(viii)What factors influence the thermal expansion of solids?
The nature of the material (α), the original length or volume, and the change in temperature.
Part – II
NOTE:- Attempt any two questions.[9×2=18]
5.(a) How does thermal expansion differ between solids, liquids, and gases? Provide examples to illustrate these differences.
Solids: expand least because particles are tightly bound (railway tracks, bridges). Liquids: expand more, about 10 times more than solids (mercury in a thermometer). Gases: expand the most because forces between molecules are negligible (a balloon in the sun).
(b) A container holds 1 litre of water at 20 °C. What will be its volume at 80 °C, assuming water’s coefficient of volume expansion is 2.1×10-4 per °C?
ΔT = 80 − 20 = 60 °C; V0 = 1000 cm3
ΔV = βV0ΔT = 2.1×10-4 × 1000 × 60 = 12.6 cm3
V = 1000 + 12.6 = 1012.6 cm3 (1.0126 L)
ΔV = βV0ΔT = 2.1×10-4 × 1000 × 60 = 12.6 cm3
V = 1000 + 12.6 = 1012.6 cm3 (1.0126 L)
6.(a) What are some practical consequences of thermal expansion in everyday life, such as in construction materials or household appliances?
Expansion gaps in bridges and railway tracks; gaps in concrete roads; bimetallic strips in thermostats, irons and fire alarms; cracking of glass when heated suddenly; overhead cables sagging in summer.
(b) A steel bridge expands by 5 cm on a hot summer day. If the bridge originally spanned 100 m, what is the temperature change?
ΔL = 5 cm = 0.05 m, L0 = 100 m, α(steel) = 1.2×10-5 °C-1
ΔT = ΔL / (αL0) = 0.05 / (1.2×10-5 × 100) = ≈ 41.7 °C
ΔT = ΔL / (αL0) = 0.05 / (1.2×10-5 × 100) = ≈ 41.7 °C
7.(a) What is latent heat, and why is it important in phase transitions like melting and vaporization?
Latent heat is the heat absorbed or released by a substance during a change of state at constant temperature (Q = mL). It supplies the energy needed to break or form intermolecular bonds, so the temperature stays constant during melting (Lf) and vaporization (Lv).
(b) How much heat is required to melt 500 g of ice at 0 °C into water at 0 °C? (Latent heat of fusion of ice = 3.36×105 J kg-1)
m = 500 g = 0.5 kg
Q = mLf = 0.5 × 3.36×105 = 1.68×105 J
Q = mLf = 0.5 × 3.36×105 = 1.68×105 J
