Question

1 the picture illustrates energy transfer.
which statement lists the correct methods of energy transfer?
a a = radiation, b = conduction, c = convection
b a = convection, b = conduction, c = radiation
c a = radiation, b = convection, c = conduction
d a = convection, b = radiation, c = conduction
2 which of the following best illustrates thermal energy transfer by conduction?
a air getting warmer above a fire
b the earth being warmed by the sun
c metal spoon getting warmer in a bowl of hot water
d a hot air balloon rising from the flammable gas being released

Explanation:

For Question 1:

• A (upward arrows from kettle): Hot air/water vapor rises, this is convection (transfer via fluid movement).
• B (arrow to kettle base): Heat moves from the heat source through the solid kettle base, this is conduction (transfer through direct contact in solids).
• C (arrow outward from kettle): Heat is emitted from the hot kettle to the surrounding air without a medium, this is radiation.

For Question 2:

• Conduction is heat transfer through direct contact of materials. A metal spoon in hot water gets warm as heat moves from the hot water through the solid spoon via direct contact. The other options are convection (A, D) or radiation (B).

Answer:

1. B. A = convection, B = conduction, C = radiation
2. C. Metal spoon getting warmer in a bowl of hot water