Heat Radiation

Question 0

3 ways radiation is different from conduction and convection

Answer 0

Doesn’t need a medium - can occur in a vacuum (space)
Only way heat reaches us from sun
Travels through transparent surfaces (air, glass water)
Amount of radiation depends on colour and texture of surface

Question 1

What is radiation heat transfer?

Answer 1

Heat transferred as infrared waves
Electromagnetic
Travel in straight lines
Speed of light

Question 2

What colour is best for absorbing radiation?

Answer 2

Matt black

EG solar panels

Question 3

What colour is best for reflecting radiation?

Answer 3

Light coloured, smooth, shiny

EG foil on a grill

Question 4

How do toasters and grills work?

Answer 4

Toasters and grills - infrared heat radiation
Heat absorbed by particles on surface
Energy then conducted or convected to more central parts

Question 5

How do microwaves work?

Answer 5

Electromagnetic radiation
Microwaves penetrate 1cm
Absorbed by water or fat molecules, increasing kinetic energy
Energy conducted or converted to other parts