Sample Quizzes For Preparation: Transfer of Thermal Energy
O Level and IGCSE Physics – Quiz: 2.3 Transfer of Thermal Energy
1. Which process of thermal energy transfer does not require a medium?
A. Conduction
B. Convection
C. Radiation
D. Conduction and convection
2. Why are metals good conductors of heat?
A. They are shiny
B. They have vibrating atoms
C. They have free (delocalised) electrons
D. They expand when heated
3. Which is the best emitter of infrared radiation?
A. Shiny silver surface
B. Dull black surface
C. Smooth white surface
D. Polished copper surface
4. What is the main cause of convection in fluids?
A. Movement of electrons
B. Molecular vibration
C. Difference in temperature causing density changes
D. Change in pressure
5. In the Leslie cube experiment, which surface emits the most infrared radiation?
A. Polished silver
B. Dull black
C. White painted
D. Shiny metal
6. Which of the following is a poor conductor of heat?
A. Aluminium
B. Copper
C. Plastic
D. Iron
7. Which material would be the best absorber of infrared radiation?
A. White shiny surface
B. Silver mirror
C. Dull black surface
D. Transparent glass
8. Why does a hot metal rod conduct heat from one end to another?
A. Heat flows from cool to hot
B. Free electrons carry energy
C. Convection currents are formed
D. Air particles transfer energy
9. How is the volume of a gas affected when temperature increases (at constant pressure)?
A. Decreases
B. Remains same
C. Increases
D. Becomes zero
10. Which of the following shows convection in air?
A. Vibration of particles
B. Movement of hot air upward
C. Reflection of radiation
D. Condensation of water
11. Which method of heat transfer is responsible for warming your hand when near a fire?
A. Conduction
B. Convection
C. Radiation
D. Insulation
12. What happens to the density of a fluid when heated?
A. Increases
B. Decreases
C. No change
D. First increases then decreases
13. Why does black clothing feel hotter in the sun?
A. It reflects radiation
B. It emits radiation
C. It absorbs more radiation
D. It insulates the body
14. Which is NOT an example of convection?
A. Boiling water
B. Land and sea breeze
C. Heating a metal rod
D. Circulation of air in a room
15. What is the main method of heat transfer through vacuum?
A. Conduction
B. Convection
C. Radiation
D. None
16. Which of the following surfaces would reflect most infrared radiation?
A. Dull black
B. White rough
C. Shiny silver
D. Matte grey
17. How does insulation reduce heat loss in a thermos flask?
A. Allows convection
B. Increases conduction
C. Prevents radiation
D. Prevents conduction and convection using vacuum
18. Which of the following statements about conduction is true?
A. Occurs only in gases
B. Requires movement of particles from one place to another
C. Metals conduct heat mainly through free electrons
D. Always requires a vacuum
19. Which part of a metal rod receives heat last during conduction?
A. Middle
B. Near the heat source
C. Far end
D. The part not in contact with heat
20. What determines how quickly an object loses heat by radiation?
A. Its density only
B. Its specific heat capacity
C. Its surface area and temperature
D. Its height
21. Why is convection not possible in solids?
A. Solids don’t conduct heat
B. Particles in solids are free to move
C. Solids don’t emit radiation
D. Particles in solids are tightly packed and cannot flow
22. How does a vacuum between double-glazed windows reduce heat loss?
A. Prevents radiation
B. Allows conduction only
C. Prevents conduction and convection
D. Allows convection but blocks radiation
23. Which of the following transfers heat mainly by convection?
A. Metal spoon in tea
B. Sunlight heating Earth
C. Electric heater heating air
D. Radiation from fire
24. What happens in convection when fluid is cooled?
A. It expands
B. Becomes less dense and rises
C. Becomes denser and sinks
D. It turns into gas
25. Why does a silver teapot keep tea warm longer?
A. Silver absorbs more heat
B. Silver is a poor emitter of radiation
C. Silver conducts heat quickly
D. Silver radiates heat quickly
26. What is the direction of energy flow in conduction?
A. From cold to hot
B. In all directions
C. From hot to cold
D. Only upward
27. What type of energy transfer happens in boiling water on a stove?
A. Conduction only
B. Radiation only
C. Convection only
D. Conduction and convection
28. Which physical factor increases the amount of infrared radiation emitted?
A. Smaller surface area
B. Lower surface temperature
C. Higher surface temperature
D. Shiny surface
29. What is the main way heat is lost from the roof of a house?
A. Conduction through bricks
B. Convection currents inside
C. Radiation from the roof surface
D. Evaporation
30. Which one of these methods transfers heat through electromagnetic waves?
A. Convection
B. Conduction
C. Radiation
D. Evaporation
Answer Key and Explanations – O Level and IGCSE Physics Quiz: 2.3 Transfer of Thermal Energy
1. C. Radiation
Radiation does not require a medium; it can transfer heat through vacuum.
2. C. They have free (delocalised) electrons
Metals conduct heat mainly via free electrons which transfer energy rapidly.
3. B. Dull black surface
Dull black surfaces are the best emitters of infrared radiation.
4. C. Difference in temperature causing density changes
Convection occurs due to heated fluid becoming less dense and rising.
5. B. Dull black
In the Leslie cube, the dull black surface emits the most infrared radiation.
6. C. Plastic
Plastic is a poor conductor and acts as an insulator.
7. C. Dull black surface
Dull black absorbs more radiation than shiny or white surfaces.
8. B. Free electrons carry energy
Heat is transferred along the metal by free electrons and lattice vibrations.
9. C. Increases
Heating a gas at constant pressure increases its volume (Charles’s Law).
10. B. Movement of hot air upward
Hot air rises due to decreased density, forming convection currents.
11. C. Radiation
Thermal radiation from fire warms nearby objects without contact.
12. B. Decreases
As fluid is heated, particles move apart and density decreases.
13. C. It absorbs more radiation
Black clothing absorbs more infrared radiation, making it hotter.
14. C. Heating a metal rod
Conduction, not convection, is the main transfer method in solids.
15. C. Radiation
Only radiation can transfer heat through vacuum (e.g., from the sun).
16. C. Shiny silver
Shiny surfaces reflect most infrared radiation and emit the least.
17. D. Prevents conduction and convection using vacuum
Vacuum prevents both conduction and convection in a thermos flask.
18. C. Metals conduct heat mainly through free electrons
Free electrons allow metals to conduct heat efficiently.
19. C. Far end
The far end of the rod receives heat last through conduction.
20. C. Its surface area and temperature
Greater surface area and higher temperature increase radiation loss.
21. D. Particles in solids are tightly packed and cannot flow
Convection requires particle movement, which is not possible in solids.
22. C. Prevents conduction and convection
Vacuum removes particles, thus preventing conduction and convection.
23. C. Electric heater heating air
Electric heaters warm air, which moves via convection.
24. C. Becomes denser and sinks
Cooling fluid increases density, causing it to sink.
25. B. Silver is a poor emitter of radiation
Shiny surfaces like silver reduce radiation loss, keeping contents warm.
26. C. From hot to cold
Thermal energy always transfers from higher to lower temperature.
27. D. Conduction and convection
The pot conducts heat, water moves heat via convection.
28. C. Higher surface temperature
Radiation increases rapidly with surface temperature (Stefan-Boltzmann Law).
29. C. Radiation from the roof surface
Roofs mainly lose heat through radiation to the surroundings.
30. C. Radiation
Radiation transfers energy via electromagnetic waves, not particles.