• 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 Resistance in Wires

Extracts from this document...

Introduction

Investigating Resistance in Wires

Plan

Aim

Our aim was to investigate the resistance of a piece of wire, and to try and find the relationship between the length of a section of wire and it’s resistance. To do this, we are planning to use a one-metre length of wire and measure off the different sections. We will take values for the amperage and voltage of each length, repeating each experiment twice to ensure accuracy. The major problem we are likely to come across is the wire heating up, as this will cause inaccuracy in the readings.

The equipment will be set up as below,

Measurements

We decided to take values of voltage and amperage, then use Ohm’s Law to find the resistance value. We will take readings at 10cm intervals between 30cm and 100cm, giving us a total of eight values. We chose to start at 30cm rather than 10cm as starting at 10cm would be too short a distance for the electricity to travel through causing over-heating of the wire leading to inaccuracy of results.

Middle

5.20

0.17

30.59

90.00

5.06

0.14

36.14

100.00

5.13

0.12

42.75

The first time we did the investigation, we got a very unreliable set of results, after investigating the cause, we deducted we had a faulty battery pack, so decided to re-do investigation, this time our results were a lot more reliable, but to ensure accuracy, we repeated each length twice

 Length

Conclusion

• We assume the cross-section of the wire is constant throughout the length, i.e. a constant diameter.

1mm diameter                                    0.950mm diameter

1 x 3.142 = 3.142 mm²                        0.950 x 3.142 = 2.985 mm²

This change in diameter will cause a funnel effect, restricting the progress of the free electrons between the atoms, This would provide inaccurate results, leading to a false impression. If this fault occurs at the start of the wire it will affect all the results, if it occurs towards the end, it would change the pattern of results, causing incorrect placement of the line of best fit.

Improving the accuracy

The accuracy of this test can be improved in many ways:

• The use of a Jockey (thin blade contact) to increase accuracy when measuring the sections of wire, guaranteeing accurate lengths.
• Higher specification (more accurate) Ammeter and voltmeter.
• Increase increment value i.e. 100cm. steps instead of 10cm, broadening  the range of results leading to a more accurate graph.
• Add one large distance to confirm analysis of linear relationship (see analysis for extrapolated result)
• The use of a constant power supply as the batteries will drain during the test, falsifying the results.
• Ensure wire is of a constant cross-section (see above).

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. ## Investigation in resistance in wires

5 star(s)

also we increased the wire lengths which have a larger maximum current value. Width of the Nichrome wire - due to the problem of heat and the weights there was a chance that it would stretch the wire, we made sure that this didn't happen by only using the minimum

2. ## Investigate the resistance of different wires and how at different lengths the voltage increases ...

This means that if there are more atoms in the way to collide with free electrons, the resistance is increased. In a length of wire, there are atoms and free electrons, so the longer the wire, the more atoms. Therefore, there will be more collisions between the atoms and electrons, this will increase the resistance.

1. ## Physics Coursework Investigating Resistance of wires and its relationship to length.

I set up my circuit and tested Nichrome, Constantin and Copper. I didn't test Tin because the school did not have any available. Nichrome: Length (mm) Current (i) Voltage (v) 500 0.65 3.09 600 0.52 3.06 700 0.48 3.32 800 0.45 3.33 These are good results, that would be good to put on a graph and show a clear correlation.

2. ## Resistance of wires

after the copper wire; but the ammeter can be placed anywhere in the circuit, as long as it interfere with the voltmeter's connection. Then, as each different length of wire (measured by hand with a ruler) is connected to the circuit, the readings are recorded off the voltmeter and ammeter and put into a table.

1. ## Resistance and Wires

8.95 8.60 8.53 8.69 16.0 15.4 15.2 15.5 To show how the resistance was calculated, here is an example of the process of calculating resistance. This calculation was for the first recording of the mean of 10cm of wire. I used the formula, V�I=R. (1.00+0.97+0.93) � 3 = 0.97 (mean).

2. ## Resistance of Wires

I said that I would vary the number of cells in the preliminary work to determine how many to use in the actual experiment; however, with one cell, the current went above 1A (which I said I would not do), so continued to use only one cell.

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