• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Resistance of a wire. Jack has been given a second hand D.C. dynamo and lamp. He wants to attach these to his bicycle and produce most light without blowing the bulb. What wire should he use?

Extracts from this document...

Introduction

GCSE physics coursework: Resistance of a wire

Scenario:

Jack has been given a second hand D.C. dynamo and lamp. He wants to attach these to his bicycle and produce most light without blowing the bulb.

What wire should he use?

Variables:

The variables in our investigation are…

  • The length of the wire
  • The diameter of the wire (SWG)
  • The type of wire

Types of wire:

Nichrome: 80% Nickel 20% Chromium Alloy.

Constantan: 60% Copper 40% Nickel Alloy.

Copper

First of all we decided to test the resistance using a Multimeter. This would give us a rough idea about what the resistances of each wire are.

Our lengths of wire were all 30cm long.

Our results were as follows…

WIRE

RESISTANCE Ω

Copper

0.6

Nichrome

1.2

Constantan

4.3

Later we realised that we were using wires with completely different SWGs.

To make it a fair test we needed to use wires with the same SWG.

We repeated the test using a length of 30cm and an SWG of 32.

Our results were as follows…                    Our results changed dramatically.

WIRE

RESISTANCE Ω

Copper

0.9

Nichrome

5.8

Constantan

2.9

Testing the current + Voltage

Next we decided to test the current and voltage so that we could get a more accurate figure for the resistance.

We set up a circuit consisting of, a power pack, ammeter and variable resistor in series.

...read more.

Middle

0.44

0.44÷0.12

3.667


As you can see there is a correlation between the SWG and the resistance, this is that the lower the SWG the lower the resistance. We now decided to back this up with results from a Multimeter.

SWG

Resistance (Ω)

18

0.5

24

1.3

26

1.7

32

2.8

34

4.5


Testing SWG using Multimeter …..









As you can see, the results aren’t exactly the same but they still show the correlation that the lower the SWG the lower the resistance. This is because I lower SWG has a smaller diameter; this allows more electrons to flow through the wire.

After this we decided to choose the SWG 18 constantan as the type and diameter of wire we used. This is because it has the least resistance yet it is the thickest, therefore it will not get to hot too easily.                        

Now we decide to test length to test which has the lowest resistance and which is the most practical, we are using the same circuit as we used earlier in our experiment except this time is the length. We tested 6 different lengths from 10cm going up in 10 cm to 60 cm.
We also kept the voltage on 2 volts; our results were as followed ….

Length (cm)

Voltage (V)

Current (I)

Resistance (Ω)

10

0.05

0.13

0.385

20

0.12

0.13

0.923

30

0.03

0.14

0.214

40

0.11

0.13

0.845

50

0.05

0.14

0.356

60

0.04

0.14

0.286


After taking these results we realised that there should have been a correlation between the length and the resistance, that is that the longer the wire the greater the resistance. We repeated the experiment and exchanged the variable resistor for a different one, after doing this we got these results …..

Length (cm)

Voltage (V)

Current (I)

Resistance (Ω)

10

0.01

0.15

0.02

20

0.01

0.14

0.09

30

0.02

0.14

0.14

40

0.03

0.14

0.21

50

0.03

0.14

0.27

60

0.05

0.14

0.36

...read more.

Conclusion




Conclusion

For my wire I would like to you constantan wire with an SWG of 18 and a length of 35 cm. This is because the data I have collected suggests this will have the least resistance making it efficient and it is also a very practical length and diameter. I have the upmost confidence in the accuracy and reliability results and data I have collected and the only weakness is the lack of accuracy I received from the ammeters and voltmeters, but even with this weakness I still managed to get a correlation in the final test of my experiment. Another reason I have confidence in my results is because of the precision I made sure of in my testing, with this precision and correlations in all of my graphs I consider my choice of wire to be a successful choice. If I could have collected any more data in my tests it would be the choice of diameter in my wire. As I only had 5 to test a greater range in the diameters I had to choose from would have improved the accuracy of the final wire chose.




William Lavelle-Bowden 10 Triple

...read more.

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

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. Marked by a teacher

    Draw stress and strain graphs for the metal copper and the alloy constantan. Calculate ...

    4 star(s)

    and clamp it onto the G-clamp and extend the wire so it is hanging over the pulley. 6. Attach mass hanger to the end of the wire which is at the end of the pulley and then place the marker on the wire where the metre rule reads 0 centimetres.

  2. Marked by a teacher

    Investigation into the Physics of a Light Dependent Resistor.

    4 star(s)

    This is true in real atoms also. When light strikes an electron, enough energy can be transferred so that it has enough energy to move to a free outer shell i.e. one that is not full. The vertical arrow represents the movement of the electron below it, to an empty outer shell after the photon strikes it.

  1. Peer reviewed

    How does the power dissipated by a light bulb vary with voltage?

    5 star(s)

    I will measure the voltage using a voltmeter, connected in parallel through the light bulb. Dependant - My dependant variable will be the current passing through the circuit. I will find out the current by using an ammeter. List of equipment Voltmeter - The voltmeter will need to measure from

  2. Investigating The Characteristics Of A Filament Lamp

    Once the mean current has been calculated, the resistance could be also calculated. It is important to repeat the experiment a number of times, as if the experiment was only calculated once, the result would not be as accurate, and would be more likely to be anomalous.

  1. Choosing a light source

    This is so that the tungsten does not react with the gas that in the glass container. With normal light, when the tungsten wire gets hot, some of its particles of the evaporate from the wire and stick to the side of the glass that holds the wire.

  2. Find out (through an experiment) how much resistance a piece of copper wire will ...

    at a constant temperature is proportional to the potential difference (voltage). Therefore V � I is constant. This means that the resistance of a metallic conductor is constant providing that the temperature also remains constant. Furthermore, the resistance of a metal increases as its temperature increases.

  1. Construct and test an anemometer.

    Care had to be taken as a stroboscope can trigger fits of epilepsy, as it produces high frequency flashing lights. To record the rpm of the cups, I had to use a constant and even wind source; for this I used a fan.

  2. How does current vary with voltage in a light bulb?

    The higher the current is the greater the flow of electrons is. The current is measured with an ammeter an ammeter is connected in a circuit like so; The ammeter can be connected anywhere in a circuit because the current is the same all the way round.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work