• 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

# Factors Affecting the Resistance of a Wire.

Extracts from this document...

Introduction

Factors affecting the resistance of a wire.

Aim: to find out if and how the length of a wire affects the resistance of a wire.

Theory: Resistance is anything in a circuit that restricts the flow of electrons. It doesn’t slow them down. As the electrons pass through a wire or component energy has to be lost.

Above is a piece of wire with its atoms and electrons passing through it. When the electrons hit the particles in the conductor, they transfer some of the energy to the particles on the conductor this causes them to vibrate faster therefore the conductor heats up.

Ohms Law is when a conductor is kept at a constant temperature the current flowing through the conductor is directly proportional to the P.D. (potential difference) across its ends.

Resistance is calculated by dividing the voltage by the current.

This triangle shows how to work out Resistance in ohms

V = R

I

It also shows how to work out Voltage in volts.

I x R = V

As well as how to work out Current in ampere

V = I

R

There are 4 main factors effecting resistance, they are:

1. Temperature.
2. The cross sectional area.
3. The material.
4. The length.

As the current increases, so does the temperature of the conductor, because the electrons moving through it faster.

Middle

I have chosen to use Manganin as my wire because its resistance is constant at all voltages which shows that its tempreature doesn’t increse much when the electrons flow through it. Which shows that it would give me more acurate results when it comes to finding out if and how the length of the wire effects the resistance because it will keep the tempreature constant at hight voltages. It also has the most consistant results.

Prediction: I predict that the longer the wire the higher the resistance. This is because the electrons have further to travel and more atoms to bump into.

I found a formula called the resistivity formula in a text book. The formula was.

R ∝ L

R = Resistance

L = Length (15cm)

This means that resistance is proportinal to length.

To work out the resistance you need to add a constant and the cross sectional area of the wire. So the formula looks like this:

R = PL

A

P = Constant

A = Area (Cross sectional)

The constant for Manganin is 44 x 10-8  which is = 0.000000044

I have chose to use Manganin 24 SWG. The diameter for this is  0.56mm

0.00056m

The formula to work out the area of a circle is ∏r2

∏ = 3.141592654

r = 0.00028

r2 = 0.0000000784

∏r2 = 0.00000024630064

A = 0.00000024630064

Conclusion

Evaluation: this experiment went quite well it helped support my theory and prediction. It does this by showing that the resistance is related to the length it also supports that it is directly proportional.

As you can see form my results and graphs the accuracy of my experiment was quite good except for a few exceptions like the 50cm wire which was most probably measured inaccurately therefore giving a bad result.

My results are enough to support my theory that there is a relationship between the length and resistance as shown by my line of best fit. Also my results for the 60 and 70cm wire were exactly as I had predicted this is shown in my results table in the “How far off are my results.”

To improve this experiment if I was to do it again I would use a different wire each time as in this experiment when id done the 10cm wire it would let it cool down if it was hot and use it again this could have made my experiment inaccurate as damage could have been caused to the wire when I first used it. So next time I would cut another wire and use that one. If I had more time I could have done the experiment until I got a constant not an average this would have been more accurate as I would have had more results to back up my prediction and theory.

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. ## The factors affecting the resistance of a metalic conductor.

4 star(s)

This has a knock on effect and energises all atoms around until this energy is lost through heat. As the atoms vibrate they are more likely to hit electrons because the electrons now have less space to move through. If this is over a shorter distance there will be less atoms for the electrons to hit.

2. ## Factors Affecting the Efficiency of a Wind Turbine

A wind turbine was placed in front of a wind source (Hairdryer). The a/c output was recorded for each length. The windturbine was then equipped with another set of blades of different length. The blades were tested again by using the same technique.

1. ## Physics GCSE Coursework:Factors affecting the resistance of a wire

As done in the previous Analysis section, we calculated our results, and analyzed our graphs so that I could implement certain formulae into the experiment that would back up my conclusion. Please review the Initial research. Safety To ensure that the experiments where safe, there were certain precautions that had to be observed.

2. ## Investigate one or more factors affecting the resistance of metal wires

* Where I can avoid it, I will not touch the wire while the power supply is switched on or soon after the power supply is switched off because the wire may be hot. However, it is necessary to touch the wire to find out if it is getting hot and so I will do this with caution.

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

Firstly, what we will change, and secondly, what we will keep constant. These in turn will determine the relation ship between the length of carbon putty and its resistance, and we may also observe certain other factors. Firstly, we need to state the control variable that we will change.

2. ## Factors affecting Resistance of a wire

However, the temperature will rise once the current is passing 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. I will try and make sure the wire does not get to hot for safety precautions.

1. ## Investigating the factors affecting the resistance in a wire

of amperes (A), V is the potential difference measured across the conductor in units of volts (V) and R is the resistance of the conductor in units of ohms (?). In circuits, three equivalent expressions of Ohm's Law can be used interchangeably: The interchangeability of the equation may be represented be a triangle (see Figure 4), where V (voltage)

2. ## Investigation into the factors affecting the resistance of wire

Their resistance can be compared to the 26swg copper wire. I will also repeat all the experiments 3 times to make sure there are no one off results and to get an average resistance. Fair testing and safety: To try and make sure my results are as accurate as possible

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