Physics Chapter 16
Which will undergo the greater rate of cooling - a red-hot poker in a warm oven or a red-hot poker in a cold room (or do both cool at the same rate)?
red-hot poker in a cold room
Suppose you are served coffee at a restaurant before you are ready to drink it. In order for it to be the hottest when you are ready for it, you should add cream
right away.
Which body glows with electromagnetic waves?
both the Suns and the Earth
If air were a better conductor than it is, at nighttime the Earth would be
considerably colder.
Newton's law of cooling applies to objects that undergo _______.
cooling or warming
When air rapidly expands, its temperature normally _______.
decreases.
Thermal convection applies mainly to _______.
fluids.
When your foot stands on a tile floor, thermal energy always flows _______.
from either your foot or the tile depending on the temperature of the tile.
A good absorber of radiation is a
good emitter or radiation.
The reason the sun's radiant energy is of shorter wavelengths than the Earth's is because the sun
has a higher temperature than the Earth.
The relation ƒ ~ T tells us that high-temperature sources emit electromagnetic waves of _______.
high frequency
In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of
hydrogen.
When a volume of air is compressed, its temperature
increases.
Your feet feel warmer on a rug than on a tile floor because a rug
is a better insulator than tile.
Hydrogen and oxygen molecules in a gas sample have the same temperature. This means the hydrogen molecules, on the average, have the same
kinetic energy, but more speed.
If a poor absorber of radiation were a good emitter, its temperature would be
less than its surroundings.
Metals are both good heat conductors and good electrical conductors because of the
looseness of outer electrons in metal atoms.
One of the main reasons one can walk barefoot on red-hot coals of wood without burning the feet has to do with
low thermal conductivity of the coals.
A good reflector of radiation is a
poor absorber of radiation.
Heat travels from the Sun to the Earth by the process of _______.
radiation.
The planet Earth loses heat mainly by
radiation.
Cold water will warm to room temperature faster in a
black pot.
A liter of hot water will cool to room temperature faster in a
black pot.
Relatively speaking, do high-frequency waves have long wavelengths or short wavelengths?
short wavelengths
It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton's law of cooling
supports this common knowledge.
Both black and white road surfaces absorb sunlight. At the end of a sunny day the warmer road surface will be
the black surface.
A water-filled paper cup held in a flame will not catch fire. This is because
the paper cup cannot become appreciably hotter than the water it contains.
The higher the temperature of an object
the shorter the wavelengths it radiates.
At the same temperature, which move with the greater speed in the air?
very light molecules
