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How does the length of a wire affect its resistance

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Introduction

Muna Ali-11K7

GCSE Coursework-Physics Ms Wainaina

How does the length of a wire affect its resistance?

Aim:

The aim of this investigation is to find out how the length of a wire affects its resistance in a circuit.

Introduction:

Resistance is the measure of how hard it is to get a current through a component in a circuit at a particular potential difference. Varying the resistance in the circuit can control the current through a circuit.

The greater the resistance the harder it is for the current to flow and the move energy that is converted to heat and light. Resistance is measured in Ohms (Ω).

Electricity is conducted through a wire, which also means in a wire, by free electrons. The amount and number of these free electrons depend entirely on the more material, meaning that the more free electrons there are, the better the conductor. Electrons that are free are given energy as a result of moving and colliding with other nearby free electrons. This also happens across a length of wire, which means therefore, that electricity is conducted. Resistance is the results of energy loss and heat. This involves the collisions between the free electrons and also the fixed particles of the metal, free electrons and other impurities from the metal. These electrons continually collide, and therefore these collisions result in converting some of this energy that the free electrons are carrying into heat. Therefore, the wire becomes hot.

In 1826, Georg Ohm discovered that:

...read more.

Middle

I then moved the crocodile clips to 20 cm so this length of wire could be measured.I recorded the current and the voltage for 20cm of wire from the voltmeter and ammeter.I then moved the crocodile clips to 10 cm so this length of wire could be measured.I recorded the current and the voltage for 10cm of wire from the voltmeter and ammeter.This was carried out three times for each length of wire so as the result could be much more accurate and an average could be calculated for the resistance.

Obtaining Results

Below are the results of how wire affects the resistance. Three different sets of results were collected, than an average result was calculated for the resistance. The resistance in each table was multiplied by 100 so as the results will be easier to calculate a trend in a line graph.

Test 1

Length

Current

Voltage

Resistance

Resistance x 100

100cm

1.03

0.10

0.097 to 3sf

9.7

90cm

0.93

0.08

0.086 to 3sf

8.6

80cm

0.94

0.07

0.077 to 3sf

7.4

70cm

0.95

0.07

0.073 to 3sf

7.3

60cm

0.96

0.05

0.052 to 3sf

5.2

50cm

0.96

0.04

0.041 to 3sf

4.1

40cm

0.97

0.03

0.030 to 3sf

3.1

30cm

0.98

0.03

0.030 to 3sf

3.1

20cm

0.99

0.02

0.020 to 3sf

2.0

10cm

1.02

0.01

0.009 to 3sf

0.9

Test 2

Length

Current

Voltage

Resistance

Resistance x 100

100cm

0.91

0.10

0.109 to 3sf

10.9

90cm

0.93

0.09

0.096 to 3sf

9.6

80cm

0.94

0.09

0.095 to 3sf

9.5

70cm

0.95

0.07

0.073 to 3sf

7.3

60cm

0.97

0.06

0.061 to 3sf

6.1

50cm

0.98

0.06

0.061 to 3sf

6.1

40cm

0.98

0.05

0.051 to 3sf

5.1

30cm

0.99

0.04

0.040 to 3sf

4.0

20cm

1.01

0.03

0.031 to 3sf

3.1

10cm

1.02

0.02

   0.021 to 3sf

2.1

...read more.

Conclusion

To make and investigate the resistance further, I should have used different wires and tested them fully. Whereas in the preliminary I took only one reading of three different wires, as do that I could familiarise myself with the investigation.

I could have also changed such aspects as mentioned in the fair test section, such as changing the temperature to find out also if temperature in any way affects the resistance. I could have also changed and varied the width of the wire, as I have already found out that length of wire does affect resistance and whether the width also affects it. I could have also tested out different wire such as nickel chrome, Constantine as in the preliminary results to find out different resistances of different wires.

I could have also, to make the investigation more accurate by measuring the temperature of the wire to find out whether different lengths of wires have different temperatures so as this may affect the resistance

Overall, I feel the investigation was a success, and I believe I have achieved my aim of finding out how the length of wire affects the resistance. This is, as the length of wires increases, so does the resistance also increases, due to more electrons colliding with each other.

Bibliography

  • OCR Science Double Award B Phase 2 Modules
  • Nelson Thornes “Physics For You”
  • www.gcsebitesize.com
  • www.howstuffworks.co.uk

...read more.

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