# Investigation to find how the length of wire affects the resistance in a circuit.

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Introduction

## Investigation to find how the length of wire affects the resistance in a circuit

## Hypothesis

I hypothesize that the greater the length of wire, the greater the resistance will be. I also hypothesize that the resistance will increase in proportion to the length of wire.

Integrated Science 1, pg. 138, backs up my hypothesis.

What is current?: Current is the speed with which electrons flow around a circuit. The higher the current, the higher the speed with which electrons flow. Current is measured in amps.

Note: in formulae, current is referred to as ‘I’ as opposed to ‘A’ or ‘C’, as current used to named the ‘electrical intensity’.

What is voltage?: A volt is a joule per coulomb. A joule is a unit of energy, and a coulomb is a measure of charge. A coulomb is equal to 6.25 billion electrons. Therefore, a volt is general measure of energy.

Voltage is referred to as ‘V’ in formulae.

What is resistance, and how does it occur?

Middle

## Results

1.5 Volts | 3 Volts | 4.5 Volts | ||||||||

Length (centimeters) | Current (amps) | Voltage (volts) | Resistance (Ohms) | Current (amps) | Voltage (volts) | Resistance (Ohms) | Current (amps) |

Conclusion

There is a pattern in the graph. If you were to double the length, the resistance would double accordingly.

The results table shows me that as the length of wire increases, so does the resistance.

From my graph, I can make new predictions. If the length of wire was 110 cm, I predict that the resistance would be approximately 7.5 ohms. I predicted this by carrying on the line of best fit.

## Conclusion

From my results, I can conclude that my hypothesis was correct, and from my graph I can conclude that all the results agree with my hypothesis.

## Discussion

I know that the movements of electrons is inhibited in a wire if there is not enough space for them to flow through, and this is called resistance. I know that a higher voltage is needed to push the current though a circuit.

The resistance in a circuit can be calculated by R = V / I.

## Evaluation

This student written piece of work is one of many that can be found in our GCSE Electricity and Magnetism section.

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