Resistance Of A Wire

GCSE Physics Coursework - Resistance of a Wire Coursework

Introduction (Theory)

In this piece of Coursework I am going to investigate the resistance in a piece of wire.

Resistance is the force that slows down the flow of electrons; this can be due to electrons colliding. The total length of the wires will affect the amount of resistance. The longer the wire, the more resistance that there will be. This is also true for thickness of wire; the thinner the wire is the more resistance.

Resistance is measured in ohms, the symbol is Ω. The equation for measuring resistance (Ω) is Voltage (V)/Current (I) =Resistance (Ω)

Aim

In this Investigation I am going to investigate how the length of a wire affects resistance.

Variables

For this investigation I will vary the length of wire to see the resistance at each length. For the controlled variables I will keep, current in circuit, width of wire, material of wire and temperature of wire the same.

Prediction

I predict there will be more resistance the longer the wire is. This is because the electrons will have more chance to collide in a longer wire, than they do in a short wire. If I had a 100 cm wire it would be double the resistance of a 50 cm wire

Method

50cm length wire is fixed to a half a metre rule. The power supply is turned on. The voltage and flow are then read off the ammeter and voltmeter, and recorded, then do the same for 5cm intervals.

Diagram

List of equipment

A voltmeter, an ammeter, a crocodile clip, a power supply, 26 nicrome wire, ruler

Safety

In order to perform a safe experiment, we will keep the voltage low (3v) so the chance of overheating is low. Also i will turn off the power supply before changing the length of the wire

Results

5 Volts wire nickel Chrome swg

Length amps Volts ResistanceΩ

50cm 0.46 1.77 3.85Ω

45cm 0.46 1.62 3.52Ω

40cm 0.46 1.43 3.11Ω

35cm 0.46 1.29 2.80Ω

30cm 0.46 1.21 2.63Ω

25cm 0.46 0.90 1.96Ω

20cm 0.46 0.80 1.74Ω

15cm 0.46 0.70 1.52Ω

10cm 0.46 0.40 0.87Ω

5cm 0.46 0.22 0.47Ω

Length amps volts ResistanceΩ

50cm 0.46 1.82 3.96 Ω

45cm 0.46 1.59 3.46 Ω

40cm 0.46 1.33 2.89 Ω

35cm 0.46 1.28 2.78 Ω

30cm 0.46 1.2 2.61 Ω

25cm 0.46 0.91 1.98 Ω

20cm 0.46 0.75 1.63 Ω

15cm 0.46 0.61 1.33 Ω

10cm 0.46 0.45 0.98 Ω

...