# How power produced by a solar cell is affected by its distance from a light source.

How power produced by a solar cell is affected by its distance from a light source.

Theory

I expect that as the solar cells are moved closer the light source the higher the power they will produce.

As light moves away from the source it spreads out at all angles the further you are from the source the less intense the light will be.

P = I V

Power = current x volts

P = FA

Power = flux x area

Flux = P/A     Area of 4 solar cells that I will use is  0.0077m2

This means that the higher the flux the higher the power as we are not changing the area of the solar cells as this remains is constant. So as flux increases so will the power and this will happen as the cells are moved closer to the light.

Diagram

Using what I know about space and the way light intensity changes the relation I expect is.             Power = 1/distance2

Plan

To measure power by a solar cell and distance light source is away form it, then to plot the distance against power to get a strong inverse relationship.

Then to plot a graph of power against 1/distance this should then give a straight line and hopefully proportionality that is what I wish to prove. To prove that power produce by a solar cell is reciprocal of distance.

I placed a light on a table pointed at an array of solar cells mounted on a stand fixed with a clamp. I will move the solar cell closer to the light source and take measurements of the volts and amps that the array produces so I can work out how much power is produced at different distances.

• Input variable is the distance the solar cells are from the light source.

• Output variable is the power given out by the solar cells.

Diagram of apparatus

The circuit I used for measuring the power was set out like this. The voltmeter in parallel measuring the potential difference across the cells and the a ammeter in series measuring the current flowing through the circuit.

As you can see I have used a resistor in the circuit this is to minimise wasted energy lost by the power supply or solar cell. If the circuit did not have a resistor in the current would flow round ...