Thermal properties of matter

Written by Dr. Hamza Farooq (Physics)

Class 9 · Physics · 10 questions

Name: ____________________ Date: ____________

What is the freezing point of pure water on the Celsius scale?
- A 0 degrees C
- B 100 degrees C
- C 273 degrees C
- D 32 degrees C
What is 0 degrees C on the Kelvin scale?
- A 0 K
- B 273 K
- C 373 K
- D 100 K
The heat needed to raise 1 kg of a substance by 1 K is its:
- A Thermal expansion
- B Heat flow
- C Specific heat capacity
- D Latent heat
How much heat is needed to raise 2 kg of water by 10 K? (specific heat of water = 4200 J/kg K)
- A 84000 J
- B 8400 J
- C 4200 J
- D 42000 J
Which state of matter expands the most for the same rise in temperature?
- A Liquids
- B All expand equally
- C Solids
- D Gases
The heat absorbed when a liquid changes to gas at constant temperature is called:
- A Latent heat of vaporisation
- B Latent heat of fusion
- C Specific heat
- D Sensible heat
Which thermometer is used to measure body temperature?
- A Clinical thermometer
- B Laboratory thermometer only
- C Barometer
- D Hygrometer
When a solid melts, its temperature during melting:
- A Becomes zero
- B Rises quickly
- C Stays constant
- D Falls
The boiling point of water at normal pressure is:
- A 0 degrees C
- B 212 degrees C
- C 50 degrees C
- D 100 degrees C
A metal rod gets longer when heated. This is called:
- A Evaporation
- B Conduction
- C Contraction
- D Thermal expansion

Answer key

1. A, 2. B, 3. C, 4. A, 5. D, 6. A, 7. A, 8. C, 9. D, 10. D

Pure water freezes at 0 degrees C under normal pressure.
T(K) = T(C) + 273, so 0 degrees C is 273 K.
This is the definition of specific heat capacity.
Q = m c delta T = 2 x 4200 x 10 = 84000 J.
Gases expand much more than liquids, and liquids more than solids.
Changing from liquid to gas at its boiling point uses the latent heat of vaporisation.
The clinical thermometer has a narrow range around body temperature.
The heat goes into changing state.
Water boils at 100 degrees C.
Solids expand on heating.