Energy Transfer

Question 1

Loft insulation

Answer 1

A thick layer of fibreglass wool laid out across the loft floor and ceiling reduces heat loss from the house by conduction and convection.

Question 2

Cavity wall insulation

Answer 2

Foam squirted into the gap between the bricks reduce convection,conduction and radiation across the gap.

Question 3

Hot water tank jacket

Answer 3

Lagging such as fibreglass wool reduces conduction and radiation.

Question 4

Draught- proofing

Answer 4

Strips of foam and plastic around doors and windows stops draughts of cold air blowing in e.g they reduce heat loss due to convection.

Question 5

How does a Matt black stove help to improve the rate of energy transfer my infrared radiation?

Answer 5

1. Black is a good emitter of infrared radiation.
2. If it has a large surface it covers more of the room
3. matt surfaces are better emitters than shiny surfaces.

Question 6

Burning 1kg of wood transfers 15MJ of energy to the stove. The stove the. Transfers 13.5MJ of energy to the room
Calculate the efficiency of the stove

Answer 6

13.5\15 = 0.9 or 90%

Question 7

Some people hear their homes using electric heaters. Other people heat their homes using a wood burning stove

What are two environmental advantages of using a wood burning stove to heat a home than heaters that use electricity generated from fossil fuels?

Answer 7

1. Wood is renewable
2. using wood conserve fossil fuels
3. Wood is a carbon metal

Question 8

In a motor the electrical energy is transferred into other types of energy. Some of this energy is useful and the rest of the energy is wasted .

1. what is the useful energy output from the electrical motor?
2. What eventually happens to the wasted energy?

Answer 8

1. kinetic energy

2. Dissipates into the surroundings

Question 9

What is geothermal energy?

Answer 9

Energy from hot rocks in the Earth.

Question 10

Hydroelectric systems generate electricity using the energy of falling water.
A pumped storage hydroelectric systems can also be used as a way of storing energy
How?

Answer 10

1. Water is pumped or moved up to a higher reservoir.

Question 11

What happens to the particles when water changes from a gas to a large liquid?

Answer 11

1. Kinetic energy of the particles is reduced and move closer together.

Question 12

Why does a window of a double glazed rather than single glazes there is less condensation on the inside of the glass
Why?

Answer 12

1. Double glazing provides better insulation

2. The inside of glass is not as cold.

Question 13

Properties of radio and microwaves

Answer 13

Both can transfer energy and can travel in straight lines.

Question 14

What is the property of microwaves that allows them to be us e for satellite communications?

Answer 14

They can pass through the ionosphere.

Question 15

In hilly areas it may be possible to receive radio signals but terrestrial television signals
Why?

Answer 15

1. Diffraction of waves around hills
2. Wavelength needs to be similar size to the obstacle/gap
3. Radio had a long enough wavelength or tv doesn’t have a long enough wavelength.

Question 16

When a person uses the shower why does the mirror go misty?

Answer 16

1. Water evaporates
   2 water molecules go in the air
2. Causes condensation on the mirror