2.10 describe how current varies with voltage in wires, resistors, metal filament lamps and diodes, and how this can be investigated experimentally

Varying current:

In a wire:

The graph forms a straight line, which means resistance is constant and current is directly proportional to voltage.

In a filament lamp:

The graph shows that, initially, as voltage increases current also increases. But then the rate of increase of current decreases as voltage increases. This happens because resistance keeps on increasing due to the heating up of the wire (the atoms vibrate more meaning it's harder for the electrons to move)

Thermistor:

 

The graph shows that, initially, as voltage increases current also increases. But then the rate of increase of current decreases as voltage increases. This happens because resistance keeps on increasing due to the heating up of the wire (the atoms vibrate more meaning it's harder for the electrons to move).

Diode:

The graph shows that, initially, as voltage increases current also increases. But then the rate of increase of current decreases as voltage increases. This happens because resistance keeps on increasing due to the heating up of the wire (the atoms vibrate more meaning it's harder for the electrons to move).