P2: 1-5

Question 1

Give 4 advantages of using photocells.

Answer 1

They are portable and can even be used in remote locations.
No pollution
They are a renewable energy source.
Do not require a lot of maintenance

Question 2

Explain how photocells work.

Answer 2

Light energy (from the sun) is absorbed by the silicon atoms in the photocells. Then the electrons from these atoms are knocked out and are free to move around, creating a direct current.

Question 3

What factors affect the amount of energy produced by a solar cell?

Answer 3

Intensity of light and the distance from the source.

Question 4

What is a direct current.

Answer 4

When the current is always in the same direction.

Question 5

How do mirrors and solar collectors keep track of the sun everyday?

Answer 5

They use motors.

Question 6

How is wind created?

Answer 6

They are convection currents in the earth’s atmosphere which are set up by the sun.

Question 7

How can a current from a dynamo be increased?

Answer 7

Using a stronger magnet; increasing the number of coils and rotating the magnet faster.

Question 8

What is an alternating current?

Answer 8

Is when the voltage switches smoothly between positive and negative values.