(Multiple choice)

(1)

A large sheet of metal has a hole cut in the middle of it. When the sheet is heated, the area of the hole will

(a) Not change.

(b) Always increase.

(c) Always decrease.

(d) Increase if the hole is not in the exact center of the sheet.

(e) Decrease only if the hole is in the exact center of the sheet.

(2)

Mountaineers say that you cannot hard boil an egg on the top of Mount Rainier. This is true because

(a) The air is too cold to boil water.

(b) The air pressure is too low for stoves to burn.

(c) Boiling water is not hot enough to hard boil the egg.

(d) The oxygen content of the air is too low.

(e) The eggs always break in their backpacks.

(3)

If the absolute temperature of an object is tripled, the rate at which it radiates thermal energy

(a) Triples.

(b) Increases by a factor of 9.

(c) Increases by a factor of 27.

(d) Increases by a factor of 81.

(e) Depends on whether the absolute temperature is above or below zero.

(4) True or false:

(a) During a phase change, the

temperature of a substance remains constant.

(b) The rate of conduction of thermal energy is proportional to the temperature gradient.

(c) The rate at which an object radiates energy is proportional to the square of its absolute temperature.

(d) All materials expand when they are heated.

(e) The vapor pressure of a liquid depends on the temperature.

(5)

Conduction is a method of heat transfer that

(a) Can proceed in vacuum.

(b) Involves the transfer of mass.

(c) Is dominant in solids.

(d) Depends on the fourth power of the absolute temperature.

(6)

The earth loses heat by

(a) Conduction.

(b) Convection.

(c) Radiation.

(d) All of the above.

(7)

Two cylinders made of materials A and B have the same lengths; their diameters are related by dA = 2dB. When the same temperature difference is maintained between the ends of the cylinders they conduct heat at the same rate. Their thermal conductivities are related by

(a) kA=kB/4.

(b) kA=kB/2.

(c) kA=kB.

(d) kA = 2kB.