No Longer On Exam

Question 1

What do all bodies (objects) emit and absorb?

Answer 1

Infrared radiation.

Question 2

What happens to the quantity of infrared radiation emitted by an object as temperature increases?

Answer 2

The hotter the object, the more infrared radiation it will emit.

Question 3

What is a perfect black body?

Answer 3

An object that absorbs all of the radiation that is incident upon it.

Question 4

How much radiation does a perfect black body reflect or transmit?

Answer 4

None.

Question 5

Why is a perfect black body the best possible emitter of radiation?

Answer 5

• It is a perfect absorber since it absorbs all radiation incident on it.
• A perfect absorber is also a perfect emitter.

Question 6

Other than the intensity of radiation emitted, how does increasing the temperature of an object affect its emissions

Answer 6

The wavelength distribution of any emission is dependent on the object’s temperature. The higher the temperature (the hotter the object), the more shorter wavelengths that are emitted.

Question 7

What can be said about the rates of emission and absorption for a body at constant temperature?

Answer 7

The body is absorbing and emitting radiation at the same rate.

Question 8

What can be said about the rates of emission and absorption for a body increasing in temperature?

Answer 8

The body is absorbing radiation faster than it is emitting it.

Question 9

Give 2 factors that affect the temperature of the earth

Answer 9

• The earth’s rate of absorption and emission of radiation.

- The amount of radiation reflected into space.