P2 Energy transfer by heating

Question 1

What are the best conductors of energy?

Answer 1

Metals

Question 2

what is conduction?

Answer 2

the process of heat being directly transmitted through a material or substance when there is a temperature difference

Question 3

what is the thermal conductivity of an object?

Answer 3

a measure of its ability to conduct heat

Question 4

what is the relationship between thermal conductivity and energy transfer?

Answer 4

the higher the thermal conductivity of an object, the higher the rate of energy transfer by conduction across the material

Question 5

what are examples of substances with high thermal conductivity?

Answer 5

• diamond
• graphite
• aluminium

Question 6

what are examples of substances with low thermal conductivity?

Answer 6

• air
• steel
• bronze

Question 7

what are the factors affecting conduction?

Answer 7

• the temperature difference across the material, the greater the temperature difference, the more conduction
• thickness of the material, it is more difficult to conduct heat through thicker materials
• thermal conductivity of the material, heat conducts better in materials with high thermal conductivity

Question 8

explain one disadvantage caused by the solar cells only facing in one direction

Answer 8

• solar cells don’t track the sun
• so don’t always receive the maximum intensity of solar radiation

Question 9

what is the relationship between radiation and surface temperature?

Answer 9

the higher the temperature of an object, the more infrared radiation it emits in a given time

Question 10

what is a perfect black body?

Answer 10

an object that absorbs all radiation that hits it