PHYS CH. 16 & 17

A. decreases

When air rapidly expands, its temperature normally _________. A. decreases B. remains unchanged C. is unaffected, but not always D. increases

5400 cal (90)(1)(60) = 5400 (specific heat of water = 1 cal/gC, when ending with the unit calories)

Calculate the quantity of heat absorbed by 90 g of water that warms from 30∘C to 90∘C . Express your answer using two significant figures.

D. Insulators slow the passage of heat.

Does a good insulator prevent heat from escaping or slow its passage? A. Insulators conduct heat in a closed cycle, thereby returning it to its source. B. Insulators prevent heat from escaping. C. Insulators increase the transfer of heat. D. Insulators slow the passage of heat.

A. Walk fast.

How would you walk on red-hot coals without getting your feet burned? A. Walk fast. B. You can either walk slowly or walk fast. C. Walk slowly.

A. a wooden handle, because it is the better insulator

If you are able to grab a hot pan and pull it out by the handle without burning yourself, what kind of handle must the pan have, and why? A. a wooden handle, because it is the better insulator B. a metal handle, because it is the better insulator C. a metal handle, because it is the better conductor D. a wooden handle, because it is the better conductor

C. Metal is a good conductor of heat, whereas air is a terrible conductor of heat.

If you touch the metal sides in an oven with your bare hand, you're in trouble. But hold your hand briefly in the oven air and you're okay. What does this tell you about the relative conductivities of metal and air? A. Both metal and air are good conductors of heat. B. Neither metal nor air is a good conductor of heat. C. Metal is a good conductor of heat, whereas air is a terrible conductor of heat. D. Metal is a poor conductor of heat, whereas air is a good conductor of heat.

A. As electromagnetic waves

In what form does radiant energy travel? A. As electromagnetic waves B. As radioactive particles C. As sound waves D. As waves in the luminiferous aether

A. Short, ultraviolet

Relatively speaking, do high-frequency waves have long wavelengths or short wavelengths? Name an electromagnetic wave with higher frequency than blue light. A. Short, ultraviolet B. Long, infrared C. Short, infrared D. Long, ultraviolet

A. Objects that are good emitters are equally good absorbers, so they absorb radiation as well as emit it.

Since all objects emit energy to their surroundings, why don't the temperatures of all objects continuously decrease? A. Objects that are good emitters are equally good absorbers, so they absorb radiation as well as emit it. B. Objects that are good emitters are poor conductors, so they are insulated against heat loss. C. Objects that are poor emitters are good absorbers, so they absorb more radiation than they emit. D. Objects that are good emitters are poor absorbers, so they absorb as much radiation as they emit.

C. It will continue to remain a good insulator.

What happens to the conductive properties of wood when it gets very hot? A. It will change from being a good insulator to becoming a good conductor. B. It will continue to remain a good conductor. C. It will continue to remain a good insulator. D. It will change from being a good conductor to becoming a good insulator.

B. Free electrons can move through a material carrying heat, jostling atoms and other electrons.

What is the role of "loose" electrons in heat conductors? A. Free electrons vibrate in place, thereby absorbing heat. B. Free electrons can move through a material carrying heat, jostling atoms and other electrons. C. Free electrons travel from one end of a metal to the other without any collisions, thereby conducting heat. D. Free electrons emit electromagnetic radiation that carries heat from one end of a metal to the other.

A. Increase, decrease

When an air molecule is hit by an approaching, faster moving molecule, does the approaching molecule's rebound speed increase or decrease? How about when it hits a receding molecule? A. Increase, decrease B. Decrease, increase C. Increase, increase D. Decrease, decrease

A. It is a good insulator.

Which of the following would best describe the conductive properties of wood? A. It is a good insulator. B. It is neither a good conductor nor a good insulator. C. It is a good conductor.

A. Black, black

Which will normally warm faster: a black pot of cold water or a silvered pot of cold water? Which will cool faster? A. Black, black B. Silver, silver C. Silver, black D. Black, silver

B. The specific heat of water is greater than the specific heat of land. Water cools more slowly at night. The temperature difference drives convection and offshore winds.

Why does the direction of coastal winds change from day to night? A. The specific heat of water is less than the specific heat of land. Water cools more rapidly at night. The temperature difference drives convection and onshore winds. B. The specific heat of water is greater than the specific heat of land. Water cools more slowly at night. The temperature difference drives convection and offshore winds. C. The specific heat of water is greater than the specific heat of land. Water cools more rapidly at night. The temperature difference drives convection and offshore winds. D. The specific heat of water is less than the specific heat of land. Water cools more slowly at night. The temperature difference drives convection and onshore winds.

A. The coals are not good conductors of heat.

Why is one able to walk on red-hot coals without getting one's feet burned? A. The coals are not good conductors of heat. B. The coals are not as hot as they seem C. The coals are neither very hot, nor are they good conductors of heat.