Bennett Mechanical Test Thermodynamics and Heat 3

Question 1

Water boils at a lower temperature on top of a high mountain because:

Accepted Answer

Air pressure is lower at high altitude

Answer

Lower atmospheric pressure lets water boil at a temperature below 212°F.

Question 2

A thermos keeps drinks hot mainly by reducing which type of heat transfer with its vacuum layer?

Accepted Answer

Conduction and convection

Answer

The vacuum between walls blocks conduction and convection because there is no matter to carry heat.

Question 3

What is the change of a substance directly from solid to gas without becoming liquid called?

Accepted Answer

Sublimation

Answer

Sublimation is the direct solid-to-gas transition, as seen with dry ice.

Question 4

Two identical pots of water are heated, one covered with a lid. Which boils faster?

Accepted Answer

The covered pot

Answer

A lid traps heat and reduces heat loss by evaporation, so the covered pot boils faster.

Question 5

Which material would make the best insulator to keep a house warm?

Accepted Answer

Fiberglass batting

Answer

Fiberglass traps air pockets that slow heat transfer, making it a good insulator.

Bennett Mechanical Test Practice Test