Investigation into how the length of a piece of wire is related to the resistance.

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Investigation into how the length of a piece of wire is related to the resistance

Introduction

I am going to investigate how the length of a piece of wire is related to the resistance.

Resistance can be calculated with this equation:

                         

                voltage (in V)

Resistance (Ω) = current (in A)

So to find if the length of a piece of wire is related to the  resistance, I need to put the piece of wire in a circuit, then measure the voltage across it and the current going through it.

Apparatus

Voltmeter- measure the volts across the piece of wire

Ammeter- measures current going through the piece of wire

Micrometer- measures the thickness of the wire

Variable resister- varies current going through the wire

Power pack- supplies the power needed to make the circuit work

Bare wire- attached to meter rule which acts as a resistor.

Key Factors

Thickness of wire- this will be kept constant

Temperature- this will not be kept constant, but will be controlled

Type of wire (nichrome) - this will be kept constant.

Diagram

Method

The apparatus was set up as shown in the diagram. A piece of nichrome wire of length 200cm was cut and placed on the ruler. Sellotape was used to stick it down. Crocodile clips were clipped on both sides of the wire and a power pack was used to supply the current. The current was measured using an ammeter and the voltage was measured using a volt meter. From this the resistance could be calculated.              

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The readings were taken when the voltage was:

3 v

And the length of wire was: -

0.0 – 200.0 cm every 10.0 cm

Prediction

I think that as the length of the wire increases so will the resistance of it. I also believe that the rate at which the resistance of the wire increases will be directly proportional to the length.

Theory

As a result of the structure of all conductive metals, the outer electrons are able to move about freely even in a solid. When there is a potential difference across a ...

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