1. Why does perspiration cool the body?
a) Water on the skin is cool
b) Evaporation requires latent heat
c) Water has high specific heat
d) Water is a poor conductor of heat
Answer: b
2. At the boiling point of a liquid, its:
a) Temperature increases
b) Atmospheric pressure increases
c) Temperature remains constant
d) Vapour pressure decreases
Answer: c
3. The direction of heat flow is determined by:
a) Density
b) Energy
c) Mass
d) Temperature
Answer: d
4. The unit of heat is:
a) Watt
b) Joule
c) Therm
d) Calorie
Answer: c
5. Which causes more severe burns?
a) Boiling water
b) Hot water
c) Steam
d) None of these
Answer: c
6. Which device converts heat energy into electrical energy?
a) Ammeter
b) Hydrometer
c) Voltmeter
d) Thermocouple
Answer: d
7. When compressed air escapes from a punctured tire, the air inside:
a) Heats up
b) Cools down
c) Remains at same temperature
d) May heat or cool depending on moisture
Answer: b
8. Heat transfer from a heater coil to a cooking pot occurs by:
a) Convection
b) Conduction and convection
c) Radiation and convection
d) Conduction, convection, and radiation
Answer: c
9. Which liquid contracts initially at 4°C and then expands upon further cooling?
a) Alcohol
b) Water
c) Molten iron
d) Mercury
Answer: b
10. The four-stroke petrol engine operates on which cycle?
a) Carnot cycle
b) Otto cycle
c) Diesel cycle
d) Boyle’s cycle
Answer: b
11. How does a desert cooler work?
a) Replaces hot air
b) Removes moisture from air
c) Uses evaporative cooling
d) Rehydrates air
Answer: c
12. Cryogenics is the study of:
a) High temperatures
b) Low temperatures
c) Friction and wear
d) Crystal growth
Answer: b
13. As the temperature of a medium increases, the speed of light in it:
a) Increases
b) Decreases
c) Remains unchanged
d) Suddenly drops
Answer: c
14. Which is a poor conductor of heat?
a) Aluminium
b) Copper
c) Glass
d) Silver
Answer: c
15. Why is water used in car radiators?
a) Low density
b) Easily available
c) High specific heat
d) Low boiling point
Answer: c
16. When a copper disc with a hole is heated, the hole:
a) Expands
b) Contracts
c) Remains unchanged
d) Expands then contracts
Answer: a
17. Heating water from 0°C to 100°C causes it to:
a) Gradually expand
b) Gradually contract
c) Expand then contract
d) Contract then expand
Answer: d
18. Which principle is used to produce low temperatures?
a) Superconductivity
b) Joule-Kelvin Effect
c) Heating effect of current
d) Adiabatic demagnetization
Answer: d
19. What is 32°F in Celsius?
a) 32°C
b) 0°C
c) 100°C
d) 212°C
Answer: b
20. Unit of Planck’s constant is:
a) Js
b) Js⁻¹
c) Js⁻²
d) Js²
Answer: a
21. The hottest region of a gas flame is called the:
a) Non-luminous zone
b) Blue zone
c) Luminous zone
d) Dark zone
Answer: a
22. The temperature of distant stars is measured by:
a) Mercury thermometer
b) Gas thermometer
c) Pyrometer
d) Color thermometer
Answer: c
23. Heat from the Sun reaches Earth via:
a) Conduction
b) Convection
c) Radiation
d) Modulation
Answer: c
24. The heat of a reaction does NOT depend on:
a) Temperature
b) Reaction path
c) Physical states of reactants and products
d) Constant pressure or volume
Answer: b
25. The First Law of Thermodynamics is a restatement of:
a) Charles’s Law
b) Law of Conservation of Energy
c) Law of Heat Exchange
d) Newton’s Law of Cooling
Answer: b