Bennett Mechanical Test Thermodynamics and Heat 2 — Questions and Answers
Question 1: A metal spoon and a wooden spoon are left in the same hot soup. Why does the metal spoon feel hotter to the touch sooner?
- Metal conducts heat faster than wood (Correct answer)
- Wood absorbs more heat from the soup
- Metal has a higher specific heat
- Wood reflects the heat away
Correct answer: Metal conducts heat faster than wood
Metals are good thermal conductors, so heat travels through them quickly to your hand.
Question 2: What happens to most metals when they are heated?
- They expand (Correct answer)
- They contract
- They stay the same size
- They become magnetic
Correct answer: They expand
Heating causes the particles in most metals to move more and the material to expand.
Question 3: Heat moving through empty space from the Sun to Earth is an example of which method of heat transfer?
- Radiation (Correct answer)
- Conduction
- Convection
- Insulation
Correct answer: Radiation
Radiation transfers heat as electromagnetic waves and needs no medium.
Question 4: Why does warm air rise above a heater?
- Warm air is less dense than cool air (Correct answer)
- Warm air is heavier than cool air
- Heaters push air upward mechanically
- Cool air is attracted to the ceiling
Correct answer: Warm air is less dense than cool air
Heated air expands, becomes less dense, and is pushed up by surrounding cooler air.
Question 5: Which surface color absorbs the most radiant heat?
- Black (Correct answer)
- White
- Silver
- Mirror-polished
Correct answer: Black
Dark, dull surfaces absorb the most radiant heat while light, shiny ones reflect it.
Question 6: A bridge has gaps called expansion joints. What is their main purpose?
- To allow for thermal expansion and contraction (Correct answer)
- To drain rainwater
- To reduce the bridge's weight
- To make the bridge flexible in wind
Correct answer: To allow for thermal expansion and contraction
Expansion joints give the structure room to expand in heat and contract in cold without cracking.
Question 7: In which state of matter do particles have the most thermal energy and freedom of movement?
- Gas (Correct answer)
- Solid
- Liquid
- Crystal
Correct answer: Gas
Gas particles move fastest and farthest apart, carrying the most thermal energy.
Bennett Mechanical Test Thermodynamics and Heat 2
A metal spoon and a wooden spoon are left in the same hot soup.
Why does the metal spoon feel hotter to the touch sooner?