The Resistance of a wire.

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Physics Coursework: The

Resistance of a wire

Introduction

   

   In this experiment I will be looking at the relationship between the length of the wire and the amount of resistance that occurs. This will involve measuring the current and voltage for wires of different lengths we will measure it against a meter ruler. It will then be connected to a power supply of 2 volts. Also in the circuit there will be an ammeter and a resistor and voltmeter that will be parallel to the length of the wire.

Symbol key:

        = Cells (power supply)                        = wire

        = Ammeter                = Voltmeter        

        =  Variable Resistor

Diagram

 The way in which the apparatus have been set will allow us to measure the current and voltage increasing or decreasing. If we change the length of the wire we’ll be able to see the changes.

    We plan to take the measurements from the 2 voltmeters placed parallel to the resistor and nichrome wire. These measurements will give us the results in order to see if the length of the wire affects the voltage in the circuit.

    By putting an ammeter in the circuit I can record the changes in how the length of the nichrome wire affects the current.

    For each of the separate pieces of wire we will calculate the resistance using the voltage and current.

Pilot Test

For this test I will be looking to see if whether the measurements and settings will tell me the different aspects on what affects the Resistance of a wire. For this test I will take the resistance of 100mm and 1000mm pieces of wire, if there ratio of 100 to 1000 is 1:10 then perhaps the other measurements may follow the same pattern.

Plan

For the test I will be using 2 volts and nicrome wire, there are going to be collisions of electrons so to find out how many I will be taking the readings and from the voltmeter and ammeter. From these readings I will be able to use the formula for working out resistance which is V .

         I

Using the same diagram and equipment for the main experiment I have set the clips on the wire to the 100mm and 1000mm points. These are the readings below;

Results and Findings

The readings that I got for the resistance are very interesting because the second resistance reading was almost exactly 10x the resistance of the first reading.

100 x 10 = 1000

1.052 x 10 = 10.52

My resistance reading for 1000mm was 10, only 0.52 of the first reading, almost perfect correlation perfection. If these two readings follow this pattern of ratio than there might be some sort of positive correlation between the length of the wire and the resistance. I will investigate this matter further by looking at the other different lengths.

Aim

The aim of this scientific investigation is to find out what affects the resistance of a wire, this will include looking at the different aspects as to what may have affected my results and findings. Once the resistance through looking at my scientific knowledge I will come to a conclusion as to what made and affected the results I got.

Outline of Investigation

Using the equipment as displayed in the diagram at the beginning I will be taking the readings of the Ammeter and Voltmeter whilst current is being ran through the nicrome wire. I have already found one occurrence through the ratio of the wire. This has lead me to believing that there may be a positive correlation between the length of wire and the amount of resistance accumulated by the different lengths of wire. Basically all I will be doing is moving the crocodile clips to the different points on the wire in order for me to obtain the appropriate readings from the ammeter and voltmeter, thus this will allow me to obtain the resistance of the different lengths of wire. The results I will then have obtained at the end will allow me to come to a firm conclusion depending on the analysis of my results and scientific knowledge.

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Fair test

In order to get a good set of results the tests will have to be fair. To make this experiment a fair test we will need to keep some points the same although some will obviously change. Parts that we will need to keep the same, the voltage is one of them. It will always stay the same although we need to change the length of wire to see how the resistance changes. Although the changes in the resistance will hopefully provide a good interpretation to which factors affect the resistance.

   Another point that will ...

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