# Revise GCSE Physics

Question:What factors affect the amount of electric current produced by a photocell?

The current and power produced in a Photocell depends on:

Light intensity

Surface area exposed

Distance from the light source.

Intensity means how much power is in each square meter of light.

At the surface of the Earth the peak Intensity of Sun light is about 1000 watts per square meter.

So 1000 Joules of Solar Energy fall on every square meter of the Earth's surface every second.

A second way to increase the amount of energy hitting a solar panel is to make the panel bigger.

So the power or current produced by a photocell depends on the surface area exposed to Sunlight.

The angle that the light hits the photocell also has an effect because hitting the photocell at a larger angle reduces the intensity of the light.

Lastly, light from most sources spreads out in all directions.

So the intensity of light decreases as the light spreads out because it is divided up across a larger area.

Sunlight spreads out in a spherical manner.

So as the distance from the Sun increases, the intensity decreases because the spherical surface that the light is spread across is getting larger in area.