I am going to carry out an experiment to test what can be changed in a circuit to affect the resistance.

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Introduction

We all know that current is the flow of electrons through an electrical circuit (the electrical charge), but before the electrons flow through the circuit, a voltage (or potential difference) must be applied. This provides the “pressure” to push the electrons forward. A battery for example would give a potential difference to a circuit and provide the force to begin the flow of electrons through it.

Resistance is measured in Ohms (Ω). It is anything in the circuit that opposes the flow of an electrical charge. Every component in a circuit causes a resistance (even the wire). The resistance in a circuit can be found by using this formula:

‘R’ is the resistance

‘V’ is the voltage

‘I’ is the current

For example, if the voltage in a circuit is 6volts and the current is 3amps then the resistance in that circuit would be 2Ω, as 6 / 3 = 2.

These variables are all relational. If you change one then it will affect the others. The formula to work out the voltage and current in a circuit are as follows:

I am going to carry out an experiment to test what can be changed in a circuit to affect the resistance. I will then record the results I get and analyse them to find out why and how it affects it.

Plan

I am going to find out how changing the length and thickness of wire in an electrical circuit will affect the resistance.

The equipment I am going to use is:

  • A power pack (set to 4 volt output)
  • A rheostat (Can be set to various strengths to control the voltage of the circuit and provide more accurate results when a average is taken, also stops the wires from getting too hot)
  • An ammeter (Records the current through the circuit)
  • A voltmeter (Records the voltage given to the circuit)
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I decided on using this equipment because I have used these before in previous experiments and they proved to be most very reliable and trustworthy.

I will set up the equipment as follows:

The blue wire in the centre will be the variable area. The various different wires that are being tested go here, the rest of the circuit stays constant at all times to ensure a fair test (save the rheostat – the reason for this will be explained in the method).  

The wire I am going to test is Nichrome wire. ...

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