P2

Question 1

testing rods of different materials

Answer 1

• metals conduct energy better than non-metals
• copper is a better conductor than steel
• glass conducts better than wood

Question 2

thermal conductivity

Answer 2

The higher the thermal conductivity of a material, the higher the rate of energy transfer through it

Question 3

insulation matters

Answer 3

The thicker a layer of insulating material, the lower the rate of energy transfer through it

Question 4

energy from the sun

Answer 4

The Earths atmosphere blocks radiation types that are harmful to people, but doesn’t block infra red radiation from the sun

Question 5

radiation and surface temperature

Answer 5

The hotter an object is, the more infrared radiation it emits in a given time

Question 6

Black body radiation

Answer 6

Radiation emitted by a body that absorbs all the radiation incident on it

Question 7

absorption and emission of infrared

Answer 7

The temperature of an object increases if it absorbs more radiation than it emits.

Question 8

the Earths temperature

Answer 8

depends on the absorption of infrared radiation from the sun and the emission of radiation from the Earths surface and atmosphere

Question 9

Keeping the Earth warm

Answer 9

Greenhouse gases absorb longer wavelength infrared radiation from the earth and prevent it escaping into space. The gases absorb radiation and emit it into the surface. This makes Earth warmer

Question 10

Reducing the rate of energy transfer

Answer 10

The rate of energy transfer from houses can be reduced by using:
- loft insulation
- cavity wall insulation
- double glazed windows
- aluminium foil behind radiators
- external walls with thicker bricks and lower thermal conductivity

Question 11

Solar panels

Answer 11

absorb infrared radiation from the sun and generate electricity directly or to heat water directly