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 happens to the type of radiation emitted by an

object as temperature increases?

Answer 3

The hotter the body the shorter the wavelength
of radiation released (eg. X rays and gamma
rays)

Question 4

What is required for a body to be at a constant

temperature?

Answer 4

The body would need to emit radiation at the
same rate it absorbs it - it needs to radiate at the
same average power that it absorbs

Question 5

_____ and ____ distribution of any

emission depends on temperature.

Answer 5

Intensity and wavelength distribution of any

emission depends on temperature.

Question 6

What is meant by intensity?

Answer 6

The power transferred per unit area; it is
a measure of the energy transferred by a
wave.

Question 7

What will happen if the average power that a object

radiates is less than it absorbs?

Answer 7

The temperature of the object will

decrease.

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

Question 10

How does the Earth’s atmosphere affect

radiation?

Answer 10

The atmosphere largely absorbs or
reflects radiation from the sun,
preventing it from reaching Earth. Some
radiation, however, is allowed to pass
through and warms the earth.

Question 11

What happens to the radiation emitted from the

Earth?

Answer 11

It is absorbed and re-emitted in all
directions by greenhouse gases,
resulting in the greenhouse effect which
warms the earth