# To investigate the factors of affecting the resistance of a wire.

Essay by trixta February 2006

Physics Coursework- Ohm's Law

Aim: To investigate the factors of affecting the resistance of a wire.

In this experiment I will be using a metal nichrome wire to show the resistance when the length and width is changed.

Variables

Variables that I am going to keep the same. Variables that I am going to change.

Width- 0.36mm2

Material- Nichrome wire

Voltage- 2V

Temperature- Room Temperature

Length- 10cm, 20 cm, 30cm, 40cm, 50cm

Material- Nichrome

Length- 50cm

Voltage- 2V

Temperature- Room Temperature

Width- 0.36mm2, 0.32mm2, 0.24mm2, 0.16mm2, 0.12mm2, 0.08mm2

In this experiment I am going to use the nichrome wire as a conductor and I will be measuring the resistance by using an ammeter and a voltmeter because electricity can pass through the nichrome wire and the voltmeter will give me the volts produced and the ammeter will give me the amps produce, therefore these readings can be used to find the resistance.

The resistance of a conductor is defined by the equation: R=V

I

Resistance = Potential difference (Voltage)(V)

Current (amps)

Therefore I will be using this formula to give me the resistance, where the voltage divided by the current will equal the resistance.

Metals conduct electricity because the atoms in them do not hold on to their electrons very well, and so creating free electrons, carrying a negative charge to jump along the line of atoms in a wire. Resistance is caused when these electrons flowing towards the positive terminal have to 'jumps' atoms. So if we double the length of a wire, the number of atoms in the wire doubles, so the number of jumps double, so twice the amount of energy is required: There are twice as many jumps if the wire is twice as long. The thinner the wire is the less channels of electrons in...