In my physics piece of coursework I have been asked to investigate factors which can affect the amount of current flowing in a circuit. I know from physics that the higher the resistance the lower the current will be, I also know that following can affect how much current flows in a circuit:.
Length of wire – If the wire is longer it needs more force to get the electrons through the long piece of wire making the wire have a higher resistance and resulting in lowering the current.
Type of wire – Copper is a good conductor of electricity but other metals don’t conduct electricity as well so this can have an effect on the current as it will be easier for the atoms to pass through the copper wire than most other conductors of electricity.
Voltage – I also know that the higher the voltage is in a circuit, the higher the current will be.
Temperature – The higher the temperature of the wire the more resistance it has, because the atoms in wire have more energy and move more, making it harder for the electrons to pass through it, resulting in a drop in the amount of current flowing through the circuit.
Diameter of wire – The longer the diameter of the wire the easier it is for the electrons to get through, a smaller diameter would mean a higher resistance as the electrons would have to squeeze themselves through and therefore a lower current as it is harder for electrons to pass through it, an example of this is shown here in the picture to the right.
I have decided to investigate how the length of wire can affect the current flowing. To do this I will need to measure the current in a circuit using an ammeter. Secondly I will need different lengths of wire and a battery or some kind of power source. Below is a circuit diagram of what my circuit is going to look like:.
The variable resistor is included in the circuit so I can change the voltage supplied by the battery if I don’t want the voltage to be too high.