6.3 BLACK BODY RADIATION

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.

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 two factors that affect the

temperature of the Earth.

Answer 9

1. The Earth’s rate of absorption and
   emission of radiation
2. The amount of reflection of radiation
   into space