P2 - Collecting energy from the sun

Question 1

What is a photocell?

Answer 1

Photocells are devices that transfer light energy directly into electrical energy.

Question 2

What is a solar cell?

Answer 2

A solar cell is a photocell that uses light from the sun.

Question 3

What are the advantages to photocells?

Answer 3

• need little maintenance
• carry on working for a long time
• no fuel needed
• renewable energy
• no pollution

Question 4

What is the main disadvantage to a photocell?

Answer 4

It does not produce electricity when it is dark.

Question 5

What does the current produced by a photocell depend on?

Answer 5

• the intensity of the light
• the distance from the light
• the surface area exposed

Question 6

What is n - type silicon?

Answer 6

Silicon that has had phosphorous added so there are electrons.

Question 7

What is the best colour for absorbing radiation?

Answer 7

Black.

Question 8

How does wind move?

Answer 8

Through convection currents.

Question 9

What is passive solar heating?

Answer 9

Passive solar heating is using direct sunlight for heating purposes.

Question 10

What are the benefits of wind farms?

Answer 10

• they do not produce pollution

- they are renewable sources of energy

Question 11

What are the issues of wind farms?

Answer 11

• they produce noise pollution

- they are unattractive

Question 12

How do greenhouses work?

Answer 12

1) energy enters the greenhouse as short wave radiation
2) plants and ground absorb the radiation and then emit it as long wave radiation
3) glass reflects the radiation back inside