Investigating Resistance In a Wire

Investigating Resistance In a Wire

Plan

In this investigation I will find out how a piece of wire of different

material would affect the resistance in a series circuit. To test if

this will work I will use certain equipment such as a power supply Box

which will supply my energy which I will need. I will also use a

voltmeter and an ammeter to test for my resistance. The relationship

between Current, Voltage and resistance can be given by the Ohms Law

to which is shown by the diagram below:

[IMAGE]This means Voltage (V) = Current (I) x Resistance (R). To use

this formula I will need wires such as Nickel Chrome, Manganin,

Copper, and Constantan.

From my scientific knowledge I know that long wires have more

resistance than shorter wires and that thicker wire have more

resistance than thinner wires.

Preliminary work

Before my actual investigation, I done a short experiment to help with

the real investigation I used the wire name Nickel Chrome and the

thickness 24 SWG. My results are shown below:

Length (cm)

Current (A)

Voltage (V)

Resistance (Ω)

20 cm

2.20

2.00

0.90

30 cm

1 .66

2.20

1.32

40 cm

1.30

2.40

1.84

50 cm

1.10

2.50

2.27

60 cm

0.93

2.50

2.68

70 cm

1.81

2.60

1.43

80 cm

0.73

2.70

3.69

90 cm

0.66

2.70

4.09

100 cm

0.59

2.70

4.57

From my Preliminary work I learnt that:

· As you increase the length of the wire the resistance increases too

· The wires can get hot during the test

· To set-up the circuit every time can be difficult

Method

I will use an electronic Ammeter, which I will use to test for my