P2.2/3 - Infrared Radiation

Question 1

infrared radiation

Answer 1

electromagnetic waves between visible light and microwaves in the electromagnetic spectrum

Question 2

How are conduction/convection different from infrared radiation?

Answer 2

• conduction/convection involves the heat transfer through particles
• infrared doesn’t involve particles

Question 3

Electromagnetic waves

Answer 3

• are electric/magnetic waves

- travel through space

Question 4

Wavelength comparison of infrared and visible light

Answer 4

-infrared has a longer wavelength than visible light

Question 5

The light bulb is an example of what part of the electromagnetic spectrum

Answer 5

visible light spectrum

Question 6

How are waves sorted in the electromagnetic specturm?

Answer 6

in order of their wavelengths

Question 7

Do all waves in the electromagnetic travel at the same speed?

Answer 7

• yes
• at the speed of light through a vacuum
• 300 million m/s

Question 8

White light is made up of what colours?

Answer 8

• Red
• orange
• yellow
• green
• blue
• violet

Question 9

where is infrared located on the electromagnetic spectrum

Answer 9

next to red in the visible light spectrum

Question 10

Do all objects emit and absorb infrared?

Answer 10

• yes

- despite their temp

Question 11

The hotter an object..

Answer 11

the more infrared they emit

Question 12

A body at a constant temperature…

Answer 12

emits infrared at the same rate as it absorbs it at

Question 13

Hotter objects emit radiation…

Answer 13

at a higher intensity

Question 14

Absolute zero of an object

Answer 14

• no kinetic energy of particles in object

- so cannot absorb/emit

Question 15

A perfect black body:

Answer 15

• absorbs all radiation that hits it
• doesn’t reflect or transmit
• no other object emits/absorbs as well as this body

Question 16

transmit meaning

Answer 16

allow to pass through

Question 17

Radiation emitted by the black body is called?

Answer 17

black body radiation

Question 18

A good emitter is also..

Answer 18

a good absorber

Question 19

An object that has a constant temperature…

Answer 19

emits radiation across a continuous range of wavelengths

Question 20

In a black body graph, explain the difference between higher radiation curve and the lower curve?

Answer 20

-the higher radiation curve has a shorter wavelength

Question 21

Why does the higher radiation curve in a black body graph have a shorter wavelength?

Answer 21

• as the shorter wavelength,

- causes a greater increase in intensity of radiation

Question 22

If an object has a constant temperature..

Answer 22

the object emits infrared at the same rate it absorbs it at.

Question 23

When an object absorbs radiation faster than it emits it…

Answer 23

the temperature increases

Question 24

Earth’s temp depends on

Answer 24

• the rate that light or infrared from the sun are
  - reflected back into space or absorbed into the atmosphere
  - emitted from the Earth’s surface/atmosphere into space

Question 25

What would happen if the Earth had no temperature?

Answer 25

• its temp would plunge

- as it would not be absorbing but only emitting radiation into space

Question 26

Process of the Earth being heated by the sun

Answer 26

1. Infrared from the sun warms the Earth’s ground
2. Ground becomes hot and emits longer wavelength infrared
3. CO2 absorbs and re-emits this infrared into the ground

Question 27

The hotter the object…

Answer 27

the shorter the wavelengths of the infrared it emits