Rates Of Heat Transfer

Question 1

What 3 things does the rate of heat transfer depend upon?

Answer 1

• surface area
• volume
• the type of material

Question 2

Why does having a larger surface area mean more heat is transfered?

Answer 2

There is more surface for infrared waves to be emitted or absorded by

Question 3

Why do motorbikes have fins?

Answer 3

They increase the surface area so that heat is radiated away quicker

Question 4

Why does a higher volume mean an increase in heat transfer

Answer 4

A higher proportion of the onject will be in contact with its surroundings

Question 5

What does a material do to the rate of heat transfer?

Answer 5

If an object is a conductor the heat will be conducted away much faster than if it is in contact with a good insulator

Question 6

Explain 3 things in a vacuum flask that help it to limit heat transfer

Answer 6

The glass bottle is double walled with a vacuum between the two walls -> this stops all conduction and convection through the sides

The bottle is supported using insulating foam -> this minimises heat loss by conduction

The stopper is made of plastic filled with foam -> reducing conduction