Thermal Properties of Matter explains how heat affects temperature, size, state and energy transfer in substances. It helps students understand heating, cooling, expansion, phase change and heat transfer in daily life.
Important Questions Class 11 Physics Chapter 10 help students practise definitions, formulas, concept-based answers, numericals and reasoning questions from Thermal Properties of Matter.
This chapter connects Physics with daily examples. A metal lid opens after heating. Steam burns more than boiling water. Sea breeze changes direction after sunset.
The chapter covers temperature scales, ideal gas equation, thermal expansion, specific heat capacity, calorimetry, latent heat, conduction, convection, radiation and Newton’s law of cooling. These questions help students prepare for 2026 school exams with concept clarity and formula practice.
Key Takeaways from Important Questions Class 11 Physics Chapter 10
| Area |
What Students Should Revise |
| Chapter Name |
Thermal Properties of Matter |
| Chapter Number |
Chapter 10 |
| Main Idea |
Heat, temperature, expansion, phase change and heat transfer |
| Important Formulas |
Celsius-Fahrenheit relation, PV = μRT, Q = msΔT, Q = mL |
| High-Scoring Topics |
Thermal expansion, calorimetry, latent heat, heat transfer |
| Numericals |
Expansion, specific heat, calorimetry, conduction and cooling |
| Key Laws |
Boyle’s law, Charles’ law, Wien’s law, Stefan-Boltzmann law, Newton’s law of cooling |
| Common Mistake |
Treating heat and temperature as the same quantity |
| Best Practice |
Learn formula, unit, condition and daily-life example together |
Thermal Properties of Matter Formulas Class 11
Students should revise thermal properties of matter formulas class 11 before solving numericals. Most questions use direct formulas, but the units must stay correct.
| Concept |
Formula |
| Celsius to Fahrenheit |
(tF − 32)/180 = tC/100 |
| Kelvin to Celsius |
T = tC + 273.15 |
| Ideal gas equation |
PV = μRT |
| Linear expansion |
Δl/l = αlΔT |
| Area expansion |
ΔA/A = 2αlΔT |
| Volume expansion |
ΔV/V = αvΔT |
| Relation for solids |
αv = 3αl |
| Heat capacity |
S = ΔQ/ΔT |
| Specific heat capacity |
s = ΔQ/mΔT |
| Molar specific heat capacity |
C = ΔQ/μΔT |
| Heat during temperature change |
Q = msΔT |
| Latent heat |
Q = mL |
| Heat conduction |
H = KA(TC − TD)/L |
| Wien’s law |
λmT = constant |
| Stefan-Boltzmann law |
H = AeσT⁴ |
| Newton’s law of cooling |
dQ/dt ∝ (T₂ − T₁) |
Thermal Properties of Matter Class 11 Important Questions on Temperature and Heat
Thermal properties of matter class 11 important questions often begin with the difference between heat and temperature. Students should keep this distinction clear.
Q1. What is temperature?
Temperature is the measure of hotness or coldness of a body. Its SI unit is kelvin.
Q2. What is heat?
Heat is energy transferred between bodies due to temperature difference. Heat flows from a hotter body to a colder body.
Q3. What is the SI unit of heat?
The SI unit of heat is joule.
Q4. Why is our sense of touch not reliable for measuring temperature?
Touch gives only a rough idea of hotness or coldness. It depends on our body condition and cannot give accurate values.
Q5. What happens when a hot body touches a cold body?
Heat flows from the hot body to the cold body. The flow continues until both reach the same temperature.
Q6. Why does ice-cold water left on a table become warmer?
Heat flows from the surroundings into the cold water. This continues until water reaches room temperature.
Measurement of Temperature Class 11 Questions
Measurement of temperature class 11 questions test thermometer scales and fixed points. Thermometers use physical properties that change with temperature.
Q7. What is a thermometer?
A thermometer is a device used to measure temperature. It uses a property that changes with temperature.
Q8. Which property is used in a liquid-in-glass thermometer?
A liquid-in-glass thermometer uses expansion of liquid with temperature. Mercury and alcohol are common examples.
Q9. What are the fixed points in Celsius scale?
The ice point is 0°C. The steam point is 100°C under standard pressure.
Q10. Convert 40°C into Fahrenheit.
Using the formula:
(tF − 32)/180 = tC/100
(tF − 32)/180 = 40/100
tF − 32 = 72
tF = 104°F
Answer: 40°C equals 104°F.
Q11. Convert 300 K into Celsius.
T = tC + 273.15
tC = 300 − 273.15
tC = 26.85°C
Answer: 300 K equals 26.85°C.
Class 11 Physics Chapter 10 Questions and Answers on Ideal Gas Equation
Class 11 physics chapter 10 questions and answers often include ideal gas equation and absolute temperature. This section also connects Chapter 10 with later Thermodynamics.
Q12. State Boyle’s law.
Boyle’s law states that pressure and volume of a fixed amount of gas are inversely related at constant temperature.
Q13. State Charles’ law.
Charles’ law states that volume of a fixed amount of gas is directly proportional to absolute temperature at constant pressure.
Q14. Write the ideal gas equation.
The ideal gas equation is:
PV = μRT
Here, P is pressure, V is volume, μ is number of moles, R is universal gas constant and T is absolute temperature.
Q15. What is the value of universal gas constant?
The value of R is 8.31 J mol⁻¹ K⁻¹.
Q16. What is absolute zero?
Absolute zero is the lowest possible temperature on the Kelvin scale. It equals −273.15°C.
Q17. Why is Kelvin scale called absolute scale?
Kelvin scale starts from absolute zero. It does not use negative temperature for ordinary thermodynamic calculations.
Thermal Expansion Class 11 Questions
Thermal expansion class 11 questions are common in exams because they connect formulas with daily examples. Thermal expansion means increase in dimensions due to temperature rise.
Q18. What is thermal expansion?
Thermal expansion is the increase in size of a body due to rise in temperature.
Q19. Name the three types of thermal expansion.
The three types are linear expansion, area expansion and volume expansion.
Q20. What is linear expansion?
Linear expansion is the increase in length of a body due to rise in temperature.
Q21. Write the formula for linear expansion.
The formula is:
Δl/l = αlΔT
Here, αl is coefficient of linear expansion.
Q22. Why are gaps left between railway tracks?
Gaps allow rails to expand during hot weather. Without gaps, thermal stress can bend the rails.
Q23. Why does a metal lid open easily after heating?
The metal lid expands on heating. Its diameter increases, so it loosens from the bottle.
Q24. What is the relation between coefficient of volume expansion and linear expansion?
For an isotropic solid:
αv = 3αl
Thermal Properties of Matter Numericals Class 11 on Expansion
Thermal properties of matter numericals class 11 need careful unit conversion. Temperature difference in Celsius and kelvin has the same numerical value.
Q25. A steel rod of length 2 m is heated through 50°C. If α = 1.2 × 10⁻⁵ K⁻¹, find increase in length.
Using:
Δl = αlΔT
Δl = 1.2 × 10⁻⁵ × 2 × 50
Δl = 1.2 × 10⁻³ m
Answer: Increase in length is 1.2 mm.
Q26. A copper sheet has a hole. What happens to the hole when the sheet is heated?
The hole expands as if it were made of the same material. Its diameter increases on heating.
Q27. Why can fixed rails bend during summer?
Rails expand on heating. If their ends cannot move, thermal stress develops and bends them.
Q28. Why does water show anomalous expansion?
Water contracts when heated from 0°C to 4°C and expands above 4°C. So, water has maximum density at 4°C.
Q29. Why do lakes freeze from the top in cold regions?
Water becomes densest at 4°C and sinks. Colder water stays at the top and freezes first.
Specific Heat Capacity Class 11 Questions
Specific heat capacity class 11 questions test heat required for temperature change. Students should remember that no phase change occurs in these questions.
Q30. Define heat capacity.
Heat capacity is the heat required to raise the temperature of a body by one kelvin.
Formula:
S = ΔQ/ΔT
Q31. Define specific heat capacity.
Specific heat capacity is the heat required to raise the temperature of unit mass of a substance by one kelvin.
Formula:
s = ΔQ/mΔT
Q32. What is the SI unit of specific heat capacity?
The SI unit is J kg⁻¹ K⁻¹.
Q33. Why is water used as a coolant?
Water has high specific heat capacity. It absorbs large heat with a small temperature rise.
Q34. Why do coastal areas have moderate climate?
Water heats and cools slowly due to high specific heat capacity. This keeps coastal temperatures moderate.
Q35. A 2 kg block absorbs 4000 J heat. Its temperature rises by 10 K. Find specific heat capacity.
s = Q/mΔT
s = 4000/(2 × 10)
s = 200 J kg⁻¹ K⁻¹
Answer: Specific heat capacity is 200 J kg⁻¹ K⁻¹.
Calorimetry Class 11 Questions
Calorimetry class 11 questions depend on one core principle: heat lost equals heat gained. This works when no heat escapes to surroundings.
Q36. What is calorimetry?
Calorimetry is the measurement of heat exchange between bodies.
Q37. What is a calorimeter?
A calorimeter is a device used to measure heat. It reduces heat loss to surroundings.
Q38. State the principle of calorimetry.
Heat lost by the hot body equals heat gained by the cold body, if no heat escapes.
Q39. Why is a calorimeter usually made of copper?
Copper conducts heat well and reaches thermal equilibrium quickly. It also has low specific heat capacity.
Q40. A 0.5 kg metal at 100°C is placed in water at 20°C. Final temperature becomes 30°C. What principle helps find metal’s specific heat?
The principle of calorimetry helps find it. Heat lost by metal equals heat gained by water and calorimeter.
Change of State Class 11 Questions
Change of state class 11 questions test melting, boiling, freezing, vaporisation and sublimation.
Q41. What is change of state?
Change of state is the transition of matter from one physical state to another.
Q42. What is melting?
Melting is the change from solid to liquid.
Q43. What is vaporisation?
Vaporisation is the change from liquid to vapour or gas.
Q44. What is sublimation?
Sublimation is the change from solid directly to vapour without becoming liquid.
Q45. Why does temperature remain constant during melting?
Heat supplied breaks bonds and changes state. It does not raise temperature until the phase change ends.
Q46. Why does boiling point increase in a pressure cooker?
A pressure cooker increases pressure above water. Higher pressure increases boiling point and cooks food faster.
Q47. Why is cooking difficult on hills?
Atmospheric pressure is lower on hills. Water boils at a lower temperature, so cooking takes longer.
Latent Heat Class 11 Questions
Latent heat class 11 questions are important for numericals and daily-life reasoning.
Q48. Define latent heat.
Latent heat is heat required per unit mass during change of state without temperature change.
Formula:
L = Q/m
Q49. What is latent heat of fusion?
Latent heat of fusion is heat required per unit mass to change solid into liquid at the same temperature.
Q50. What is latent heat of vaporisation?
Latent heat of vaporisation is heat required per unit mass to change liquid into vapour at the same temperature.
Q51. Why does steam cause more severe burns than boiling water?
Steam at 100°C has extra latent heat of vaporisation. It releases this heat when it condenses on skin.
Q52. Calculate heat needed to melt 0.5 kg ice at 0°C. Given Lf = 3.33 × 10⁵ J kg⁻¹.
Q = mL
Q = 0.5 × 3.33 × 10⁵
Q = 1.665 × 10⁵ J
Answer: Heat required is 1.665 × 10⁵ J.
Heat Transfer Class 11 Questions
Heat transfer class 11 questions cover conduction, convection and radiation. These three modes explain most heating and cooling examples.
Q53. Name the three modes of heat transfer.
The three modes are conduction, convection and radiation.
Q54. What is conduction?
Conduction is heat transfer through neighbouring particles without bulk motion of matter.
Q55. What is convection?
Convection is heat transfer by actual motion of fluid.
Q56. What is radiation?
Radiation is heat transfer through electromagnetic waves. It needs no material medium.
Q57. Why does heat from the Sun reach Earth?
Heat from the Sun reaches Earth by radiation. Radiation can travel through vacuum.
Q58. Why are metals good conductors of heat?
Metals have mobile electrons. These electrons transfer thermal energy quickly.
Conduction Convection Radiation Class 11 Questions
Conduction convection radiation class 11 questions often ask students to match examples with the correct mode.
Q59. Why does a brass tumbler feel colder than a wooden tray in winter?
Brass conducts heat away from the hand faster than wood. So, it feels colder.
Q60. Why do sea breezes occur during the day?
Land heats faster than sea during the day. Warm air over land rises, and cooler sea air moves toward land.
Q61. Why does land breeze occur at night?
Land cools faster than sea at night. Air over the sea rises, and cooler air from land moves toward sea.
Q62. Why are cooking utensils blackened at the bottom?
Black surfaces absorb heat better. A blackened bottom absorbs more heat from the flame.
Q63. Why do we wear light-coloured clothes in summer?
Light-coloured clothes reflect more radiation. They absorb less heat from sunlight.
Q64. Why is a thermos flask useful?
A thermos flask reduces conduction, convection and radiation. It helps hot liquids stay hot and cold liquids stay cold.
Blackbody Radiation and Thermal Radiation Questions
Blackbody radiation questions test Wien’s law, Stefan-Boltzmann law and emissivity.
Q65. What is thermal radiation?
Thermal radiation is electromagnetic radiation emitted by a body due to its temperature.
Q66. What is a blackbody?
A blackbody is an ideal body that absorbs and emits radiation perfectly.
Q67. State Wien’s displacement law.
Wien’s displacement law states:
λmT = constant
It means peak wavelength decreases as temperature increases.
Q68. State Stefan-Boltzmann law.
Stefan-Boltzmann law states that energy radiated per second by a perfect radiator is proportional to fourth power of absolute temperature.
Formula:
H = AσT⁴
Q69. Why does hot iron change colour when heated strongly?
As temperature rises, peak wavelength decreases. The iron first glows dull red, then yellowish and finally white hot.
Newton Law of Cooling Class 11 Questions
Newton law of cooling class 11 questions appear in theory and short numericals.
Q70. State Newton’s law of cooling.
Newton’s law of cooling states that rate of heat loss is proportional to the temperature difference between body and surroundings, for small temperature differences.
Q71. Why does hot tea cool faster at first?
At first, temperature difference between tea and surroundings is large. So, rate of cooling is high.
Q72. Why does cooling slow down later?
Cooling slows down because temperature difference decreases with time.
Q73. What condition is needed for Newton’s law of cooling?
The temperature difference between body and surroundings should be small.
Q74. A body cools from 80°C to 70°C in 5 minutes. Will it take the same time to cool from 50°C to 40°C?
No. Cooling becomes slower at lower temperature difference. It takes more time near room temperature.
Thermal Properties of Matter Class 11 Extra Questions
These thermal properties of matter class 11 extra questions help students practise reasoning beyond direct formulas.
Q75. Why does a thermometer use mercury or alcohol?
Mercury and alcohol expand uniformly over a useful range. Their volume change helps measure temperature.
Q76. Why does a gas thermometer give reliable readings?
Low-density gases show nearly the same expansion behaviour. This makes gas thermometers more reliable.
Q77. Why does a solid expand on heating?
Its particles vibrate with greater amplitude on heating. This increases average separation between particles.
Q78. Why does a bimetallic strip bend on heating?
The two metals expand by different amounts. The strip bends toward the metal with smaller expansion.
Q79. Why does heat flow from hot to cold?
A temperature difference causes heat transfer. Heat flows from higher temperature to lower temperature.
Q80. Why does boiling water remain at 100°C during boiling?
Supplied heat changes water into steam. It does not raise temperature until vaporisation ends.
Q81. Why does evaporation cause cooling?
High-energy molecules escape from the liquid surface. The remaining liquid has lower average energy.
Q82. Why is woollen clothing warm?
Wool traps air in small spaces. Air is a poor conductor of heat.
Class 11 Physics Chapter 10 Important Questions: Solved Numericals
These numericals cover the most repeated exam patterns from the chapter.
Important Questions Class 11 Physics Chapter 10: Numerical Practice
Practise these questions after revising expansion, calorimetry, latent heat, conduction and Newton’s law of cooling.
Q83. A body of mass 2 kg and specific heat 500 J kg⁻¹ K⁻¹ is heated by 20 K. Find heat absorbed.
Q = msΔT
Q = 2 × 500 × 20
Q = 20000 J
Answer: Heat absorbed is 20000 J.
Q84. A rod of length 1.5 m expands by 0.9 mm when heated through 50 K. Find coefficient of linear expansion.
α = Δl/lΔT
α = 0.0009/(1.5 × 50)
α = 1.2 × 10⁻⁵ K⁻¹
Answer: Coefficient of linear expansion is 1.2 × 10⁻⁵ K⁻¹.
Q85. How much heat converts 2 kg water at 100°C into steam at 100°C? Given Lv = 2.26 × 10⁶ J kg⁻¹.
Q = mL
Q = 2 × 2.26 × 10⁶
Q = 4.52 × 10⁶ J
Answer: Heat required is 4.52 × 10⁶ J.
Q86. A metal rod conducts heat at 200 W. If length doubles, what happens to heat current?
Heat current is inversely proportional to length.
If length doubles, heat current becomes half.
New heat current = 100 W
Q87. A body cools from 90°C to 80°C faster than from 50°C to 40°C. Why?
Cooling rate depends on excess temperature. At higher temperature, temperature difference with surroundings is larger.
Common Mistakes in Class 11 Physics Thermal Properties of Matter Important Questions
Students often confuse heat and temperature. Heat is energy transfer. Temperature measures hotness.
Common mistakes include:
- Using heat and temperature as the same quantity
- Using Celsius directly in ideal gas equation
- Forgetting that boiling point changes with pressure
- Applying Q = msΔT during phase change
- Confusing conduction with convection
- Forgetting that radiation needs no medium
- Applying Newton’s law of cooling to large temperature differences
- Missing units in expansion and calorimetry numericals
Use Q = msΔT when temperature changes. Use Q = mL during melting or boiling.
Chapter-Wise CBSE Class 11 Physics Important Questions