Establishing the Current-Voltage Relationship For a Metal Conductor

Establishing the Current-Voltage Relationship For a Metal Conductor

Investigation- To Establish The Current- Voltage Relationship For A

Metal Conductor.

In this experiment I will be investigating the current- voltage

relationship for a metal conductor.

The variables that I need to keep constant in this experiment are:

1. Thickness of the wire.

2. Length of the wire

3. Input of voltage coming from the power supply should be kept

constant.

4. Temperature of wire should be kept constant.

Firstly if the constantan wire was increased then the resistance will

be less. Thin wires have more resistance than thick wires. Secondly if

the length of the wire got longer then the resistance is greater than

a short wire. Thirdly if resistance increases and the wire heats up

the straight line on the graph I'm going to plot later on in the

project won't be a straight line thus the resistance will shoot up.

Fourthly if the amount of voltage output was 2V this would be a lot

better than 12 V due to some side effects: the temperature will

increase thus causing the constantan wire to heat up and you will have

to keep on cooling it down by turning off the power. Therefore 2 and 4

Volts are better than 6, 8, 10 and 12V.

We use constantan wire instead of copper because copper is too good a

conductor of electricity so the wire will heat up too quickly even if

we put it on the lowest out put of voltage possible. Resistance will

also be very low- difficult to measure. In this experiment we use the

resistance.

First we had to find the resistance by using the formula:

Resistance = Voltage

Current

An atom consists of a nucleus and orbiting electrons. These electrons

can create a flow of current, so the more free electrons there are,

the more conducting capability that material has; thus copper is more

conductive that iron. Alloys tend to have less free electrons so they

will be less conductive.