• 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

# Investigate how resistance can affect the amount of current flow.

Extracts from this document...

Introduction

Physics coursework.

Resistance investigation.

Introduction.

## Key factors.

The flow of electrons along a conductor (e.g. a wire) is called a current. The size of the current flowing will depend on a number of variables. Any wire will resist the flow of electron, this is affected by:

• Length of the wire
• Thickness of the wire
• Material which the wire is made of
• Temperature of the wire

Resistance

The resistance of an object is determined by the nature of the substance of which it is composed, known as the resistivity, the dimensions of the object, and the temperature. Resistivity is expressed in terms of the ohms resistance per cubic centimeter of the substance at 20° C (68° F).

The term resistance is also used when the flow of a fluid or heat is impeded. The forces of friction provide the resistance to the flow of a fluid in a pipe, and insulation provides thermal resistance that reduces the flow of heat from a higher to a lower temperature.

Property of any object or substance to resist or oppose the flow of an electrical current.

Middle

10 cm

6.50 A

0.5 V

0.08 Ω

20 cm

5.09 A

0.5 V

0.10 Ω

30 cm

3.59 A

0.5 V

0.13 Ω

Length of nichrome (thickness 32)

 Length of wire Current Voltage Resistance (Ω) = Voltage / Current 10 cm 0.26 A 0.5 V 1.92Ω 20 cm 0.13 A 0.5 V 3.84Ω 30 cm 0.08 A 0.5 V 6.25Ω

From my preliminary results I can see that copper is good conductor of electricity and huge amount of current are passing through. Also resistance was extremely low, because a lot of current was passing. On the other hand nichrome is bad conductor of electricity and current is really small. Therefore resistance is high. In my real experiment I decided to use nichrome instead of copper because I want to keep current low and have high resistance to make the graph look better.

## Aim.

In this experiment, I want to examine the effects of different lengths of the wire on the current, to examine how much the resistance is changed when we increase or decrease the length.

Method.

I started my experiment by building the circuit:

I had to cut the nichrome wires different length from 10 cm to 80 cm. I took current readings from the ammeter. I used constant voltage 1 V in the first result table and 2 V in the second result table. During the experiment I measured current twice for each length of wire. That was necessary to get the most accurate results.

Safety.

In my experiment some safety precaution were needed.

Conclusion

Our data is accurate and supports our conclusion, for instance, the duplicate results (for test1 and test2) are very close.

The method of course, was an amateur one. There can me many improvements. We could get more trusted results if we had used a better wire that would not get hot fast or become burned; such a wire won't affect our fair test because of it's getting hot or etc due to it's low quality. The noting of the current would be much more accurate if there would be some kind of memory in the ammeter, to save the results itself without us needing to keep an eye on it every time which causes small mistakes, data logging equipment in this case can be very useful.

Considering that we only had the very basic equipment to carry out this experiment, it was not bad. However it could have been better if I would have used a more accurate way to measure the length of the wire and a constant account of the temperature of the wire would help as well. This would help me to see when the temperature of the wire is back to normal again.

For this purpose I should have used a computer which detects the temperature of the wire and if the wire would get hot computer would show it.

References from: Encarta Reference Library 2002

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. ## Draw stress and strain graphs for the metal copper and the alloy constantan. Calculate ...

4 star(s)

Collect the two Newton masses and place on one two Newton mass on the mass hanger. Measure the extension created by increased load. (Extension from 0 centimetres on ruler, shown by marker on wire). Record extension created with this weight on a force extension table.

2. ## Resistance Aim: my main aim is to investigate the factors that affect the resistance ...

3 star(s)

graph: The graph passes through the origin, which concludes that , however much I increase the length, the resistance will increase by the same amount. Resistance decreases if the cross-section area is increased. An example can help to get a clearer picture; a narrow wire has fewer paths existing for the electrons to move through.

1. ## An experiment to find the resistivity of nichrome

of the material , so if there is a larger number of atoms there will be a larger number of collisions which will increase the resistance of the wire. If a length of a wire contains a certain number of atoms when that length is increased the number of atoms will also increase.

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

The theory behind this is that in any metal wire, there are a number of atoms and free electrons. Electricity is the movement of these electrons through the wire. Resistance is caused when the free electrons moving through the wire collide with the atoms making their path through the wire more difficult.

1. ## How Does Insulation Affect the Rate of Cooling?

This would be used as insulation. -Stop clock. This would be used to time the rate of cooling. -Ruler. This would be used to measure the thickness of cotton wool. -Measuring cylinder. This would be used to measure the volume of water. -Elastic bands. This would be used to secure the cotton wool in its position.

2. ## relationship between voltage and current

A black body, also called an ideal radiator, is an object that radiates or absorbs energy with perfect efficiency at all electromagnetic wavelengths. The constant defines the power per unit area emitted by a black body as a function of its thermodynamic temperature.

1. ## What factors affect the flow of current through a wire?

Also I have to consider of using a constant temperature, i.e. room temperature (25�C), and also I have to keep the cross-section of the wire constant. Prediction I predict that when I double the length of wire the current will halve and if I make the length of wire three

2. ## Finding a material's specific heat capacity

into the copper can be measured very precisely - it is far superior than other methods of heating the substances such as with a Bunsen or hot water. Also, the copper block was cylindrical because this is a similar shape to the shape of the cylindrical electric heating element and

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