# Factors affecting the resistance of resistance paper.

Extracts from this document...

Introduction

Physics Coursework

Factors affecting the resistance of resistance paper

-Planning my investigation

Variables:

- Length of resistance paper
- Shape of paper
- Thickness of paper
- Width of paper
- Type of paper

Experiment:

My independent variable will be the length of the paper, and I will measure this from 1cm into the paper each side. I will measure at 4cm intervals (e.g. 4,8,12,16,20,etc.)

My controlled variables will be the shape of the paper, the thickness, the width, and the type.

My dependent variable will be the resistance of the paper.

I will not need any safety equipment as the experiment is at a low voltage, and my apparatus is safe and reliable.

Diagram:

I will make sure that my controlled variables are accurate (e.g. very carefully controlled) so that the experiment is fairer. I will take each result three times and make an average, to have a higher degree of accuracy and eradicate anomalies.

Apparatus:

- 6 x wire
- 1 x battery
- 1 x voltmeter
- 1 x ammeter
- 1 x 470Ω safety resistor
- 1 x resistance paper (30cm x 5cm)

Prediction:

I predict that the longer the paper is, the higher the

resistance will be.

Middle

407

8

814

12

1221

16

1629

20

2036

24

2443

28

2850

To find these, I used the formula:

R24 = 6/7 x 2850 = 2442.9

(but for each value I put the resistance I wanted to find at the beginning e.g. R24, R20, R16 etc. Then I divided this number by 28(which I could round down to 7), the value which I already knew, and multiplied this all by the value of 28, which was 2850.)

Therefore, the formula is:Rn = n/28 x 2850

I used this formula to make all the predictions in the table above. These predictions rely on the fact that in this experiment, resistance increase and length increase are proportional. The reason that I think this is that during my last experiment, where I used a wire with variable length instead of resistance paper, and it was proportional. Therefore, as this experiment is very similar (substituting the wire for resistance paper), I think the graph and results will also be similar.

Conclusion

ii) reliability of my apparatus

iii) strong correlation of results

If I did this particular experiment again, I would make very few changes. One change I may make would be to increase the amount of results in my previous experiment, which I based my prediction upon. If I had done this, I could have made an average and based my predictions upon this. The danger of not doing this is that I could have based my predictions on an anomaly. I did not use just one result, but I did use only a few, which may have been the cause of the slight difference between my predicted results and my obtained results. Had I done this, I may have increased the reliability of my predictions, but this would not have affected my obtained results, so if I had only based my predictions on one result, it would not have been very important. As it was, my prediction was fairly accurate, so I obviously did not use an anomaly. This brought to the conclusion that my experiment was a success.

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