• 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
8. 8
8
9. 9
9
10. 10
10

# What affects the resistance of a wire?

Extracts from this document...

Introduction

## Physics coursework*

In this experiment I will be describing the potential difference (or voltage) as the electrical ‘pressure’ pushing the charges around the circuit. I know though that some of this pressure is dropped while pushing the charges through any form of electrical resistance in the circuit. So, the potential difference across the two ends of a resistance is just the pressure dropped across the resistance.

### WHAT IS RESISTANCE?

Current is a flow of tiny, negatively charged electrons through a conductor

Like a metal wire, Metals are particularly good at carrying a current, because they have lots of “free” electrons. This means electrons which are not bound onto a particular atom in the wire, will move through the wire if you drop the pressure across its ends. The number of free electrons depends on the material, the more electrons flowing freely the better the conductor, The free electrons are given energy and as a result move and collide with neighbouring free electrons. This happens across the length of the wire and thus electricity is conducted.

The property of the conductor restricts the flow of electricity through it.

Resistance is the result of electrons; motion is impeded. It involves collisions between the free and the fixed atoms of the wire material, and other free electrons and impurities causing less current to flow.  These collisions convert some of the electrical energy that the free electrons are carrying into heat.

Resistance opposes current, which is the flow of negatively charged electrons.

Middle

Power pack

Ammeter

Voltmeter

Copper wire

Meter Ruler

Crocodile clips

Connecting Wires

Digital multimeters will be used to measure the voltage and current this is because it is more precise and therefore easier to read. If I were to use an analogue, which has a tiny like needle that keeps on moving slightly, it would be much harder to read off.

The circuit will be set out exactly like this.

METHOD

To ensure that this investigation will go well I will stick to the method below:

The equipment is set up as shown in the diagram.

A metre long of wire is attached to a metre rule. The positive crocodile clip is attached at 0cm. And the negative (which is used as the sliding contact) is firstly set at 100cms.

The power pack is then switched on; the voltage is increased until 0.3Amps shows on the ammeter.

The voltage and current is then taken, which is read off the voltmeter and the ammeter, and then recorded.

The power pack is switched off (to make this investigations safer for the next use and also so that we do not mix the previous readings with the current use.)

Conclusion

These results could be done better. If I were to do this experiment again, I would use a longer duration for the investigation. Because we only had a fixed duration for this investigation it is more likely to create complications then get rid of them. I would use newer, more accurate ammeters and voltmeters,the experiment will be done three times with different ammeters in case of any damaged or old equipment to gain more accurate results, 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 would also investigate other factors, such as temperature, voltage and current, and see how these affect the resistance. I would also do the experiments under different conditions such as temperature and pressure to see if it makes any difference to resistance.

To further investigate, I could increase and decrease the cross-sectional area of the wire just by adding more wires and seeing if this too will affect the resistance. I already know though that the larger the cross-sectional area is the lower the resistance, this is because the negatively charged electrons moving in a current are spread out over a greater area. There is less chance of a negatively charged electron to collide with an atom, so more current can flow. Increasing the thickness of a wire decreases its resistance. I would still investigate this to make sure I am certain of my judgement.

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. ## Discover the factors affecting resistance in a conductor.

The resistance may be affected if the temperature of the conductor increases. Many laws in physics are stated to be unbreakable; however this is not how Ohms Law is defined. It does not state what must occur; it simply describes the behaviour of materials.

2. ## Resistance of a Wire Investigation

Chlorophyll, with the aid of enzymes, converts light energy into chemical energy by a complex series of processes of oxidation involving loss of electrons. In these processes carbon dioxide and water are converted to glucose and oxygen. ELEVENTH Aim: To investigate a factor that affects the rate of photosynthesis.

1. ## Investigating how the length of a Wire affects its resistance.

why there are and should be anomalous results. The main reason for this is that there are so many variables that can change that we cannot measure and keep them all constant. There may be some type of undetectable particle in a nucleus which explains my anomalous results.

2. ## To investigate how the length (mm) and the cross-sectional (mm2) area of a wire ...

This procedure will involve the use of reference books. Since I can find out what substance the wire has been made of, I can use a reference book to look up the density of the substance. After noting down the density, I will accurately weigh the wire so that I get a reading in grams to 2 decimal places.

1. ## Investigating How the Cross-Sectional Area of a Conductor Affects the Resistance of Current Passing ...

I will use different resistant wires with identical lengths. I will also keep the lengths of wire straight in order to avoid damage to the wire which could alter the surface area of the wire. To ensure that my experiment is safe I will use a resistor to control the voltage through the circuit and will limit the current through the circuit 0.50 amps.

2. ## What affects the resistance of a wire?

Prediction The coursework we are carrying out is investigating how the length of a wire affects the resistance. I predict that the longer the wire, the higher the resistance. Since current is a flow of electrons, these electrons will collide with the atoms of the wire, when travelling through the circuit.

1. ## Investigating a factor affecting the electrical resistance of a wire.

The final variable is the length of the constantan alloy wire, which is what I am going to investigate. Preliminary Work: The preliminary work I plan to do will investigate which thickness of wire is best for the investigation. It will help me to carry out my investigation by showing

2. ## Investigation: How length affects the resistance in a wire.

This could be because the temperature uncontrollably changes very slightly throughout the investigation. However, I can create a formula that will connect input variable (length of wire) to a close yet not precise resistance. R = 0.27 x Lcm/10 In this formula: R = Resistance (output variable)

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