# Resistance Investigation

Physics coursework

Hypothesis-I predict that the resistance of the resistors can be found by dividing the voltage by the current through the resistor. It can be found by finding the gradient of the best-fit line on the graph of voltage against current.

This will happen because the voltage and current are proportional so voltage will equal constant current.

The constant term is the resistance so the resistance is voltage divided by current. The gradient on the graph can be formed by dividing the unit on the y-axis by the unit on the x-axis which will be voltage divided by current or on the filament lamp graph it will be current divided by voltage.

The gradient will depend on the resistance of the resistors. Ohm’s law will be followed if the graph is a straight line through the origin, so this can be used to prove Ohm’s law is valid.

Background Information- Current is the flow of charge. Current is measured in ammeters which is the flow of electrons E.g. this is like a racing track the more cars on the track the more charge.

Voltage is the energy each electron gets. A battery pushes electrons round the circuit. The size of the push is the potential difference produced by the battery and is measured in volts.

A battery supplies energy to the rest of the circuit (chemical energy → electrical energy in the wires → light and heat energy in a lamp bulb). The potential difference can also be given in terms of these energy changes in fact the volt is equal to the joules of energy per coulomb.

So a battery supplying a potential difference of 4v gives 4 joules of energy to each coulomb of charge that passes through it.

Any electrical current provides a certain resistance to the flow of an electrical current. This can be thought of as the electrons having ...