• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7

# Investigating the resistance of resistance wire

Extracts from this document...

Introduction

David Swiggs

Cand: 7355

Centre: 53611

## Investigating the resistance of resistance wire

Problem:  “Investigate one of the factors that effects the resistance of resistance wire”

Normal wire is used for conducting electricity; the best wire is the one that gives out the same amount of electricity that was put in. The wire is made out of copper because it is a good conductor of electricity. Resistance wire is used in appliances like dimmer switches. You can control how much electricity out of the end of the wire.

Current is the movement of electrons through a structure that conducts electricity. These electrons are said to be delocalised.

Metal ions in an

ordered lattice

Localised electron clouds

associated with one particular

nucleus

Delocalised ‘mobile’ electrons

Delocalised electrons are the ones that move in metals when electricity is passed through them. An alloy is two or more metals chemically combined. Resistance wire is made from nichrome; it is an alloy of nickel and chromium. In alloys the delocalised electrons are either blocked or moped up.

## Factors

The factors that I think will affect the resistance of resistance wire are

• Length
• Diameter
• Temperature
• Material
• Condition of the wire

From the ‘physics for you’ textbook, page 254, I found out the following statements:

‘As the length increases, the resistance increases, as cross-sectional area increases, the resistance decreases, as temperature increases, the resistance of wire increases’.

I also believe that the material will alter the resistance but by how much is unpredictable.

### Plan

1. Make sure the equipment works.

Middle

Resistance

Length

The length is directly proportional to the resistance

## Preliminary work

Equipment

• Power pack
• Ammeter
• Voltmeter
• Ruler
• Sticky tape
• Eureka wire Ǿ 0.37
• 6 wires

Using the set up on the pervious page.  I will switch the power pack on. Then I will touch the end of wire B along the eureka wire and take measurements at intervals of ten centimetres. I will read both meters and record the readings on a table. To make it a fair test I will be careful to keep the current, thickness and temperature all constant.

 Length (cm) V (volts) I (current) Resistance (Ω) 100 2.5 0.5 5.00 90 2.4 0.6 4.00 80 2.35 0.7 3.56 70 2.3 0.75 3.07 60 2.25 0.8 2.81 50 2.2 1 2.20 40 2.1 1.2 1.75 30 1.9 1.5 1.27 20 1.7 2 0.85 10 1.35 3.1 0.44

The temperature rose once the current was passed through it, which will cause the atoms in the wire to vibrate, and so obstruct the flow of electrons, so the resistance will increase creating an error. In my final experiment to make it fair I have to keep the temperature constant, I will accomplish this by adding a variable resistor to the keep current the same. Therefore if the current is the same the wire will not heat up.

#### Final Experiment

I will perform this experiment the same as I did in my preliminary experiment except I have added a variable resistor to keep the current the same and the temperature constant.

Conclusion

If I were to do the experiment again I would a more accurate method of measurement and take a much wider range of readings and more readings so that a more accurate average can be taken. I have also found out there is a much easier and reliable way to perform the experiment (shown below)

## I would also take readings at 5cm intervals instead of 10cm. This would obviously be more accurate and reliable, but it would also tell if the rule resistance is proportional to length if true at 5cm intervals. Ultimately I would use a lot of different types of resistance wire to see if the rule were true for all materials.

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

# Related GCSE Electricity and Magnetism essays

1. ## Length vs Resistance

A way that we could check that the wire has the same diameter all the way through it is by using a micrometer and using it to measure five points on the wire. I have decided that the factor I will be investigation will be how the length of a wire affects the resistance.

2. ## To investigate the influence of the length of a eureka wire on it's resistance.

Resistors * In a series circuit the total resistances of the circuit is the sum of all the resistances added together. * The formula used to calculate the total resistance is RT=R1+R2. If there are more resistors they will be known as R3, R4, R5...

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