• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Discover how the voltage is affected when the current flows through wires of varying lengths.

Extracts from this document...

Introduction

Helalur Rahman Khan 3894 10.1

Ohms Law

My aim is to discover how the voltage is affected when the current flows through wires of varying lengths.

Scientific Introduction

In 1826, a German physicist George Ohm stated ‘the current in a conductor is proportional to the potential difference between its ends’, providing physical conditions like temperature stay constant. The word ‘proportional’ means that when you double the potential difference the current is also doubled automatically.

Resistance is anything in the circuit that slows the flow of electrons round the circuit. This means that if you increase the resistance then the less current will flow or more voltage will be needed to keep the same current flowing. To calculate resistance you can work it out by using the formula R=V/I. This means that resistance= voltage/ current. Resistance can be affected by temperature; if the temperature is constant then the current will be proportional to the potential difference.

Using this formula for ohms law is very important as it can find you the potential difference, current or resistance using what the circuit has. The formula is:

V (Potential Difference)=I (Current) x R (Resistance)

V=IxR

Resistance is measured using resistors, all resistors produce heat when a current flows through it. The unit resistance is measured in ohms (Ω).

An electric current is the rate of flow of charge through a surface. Current is represented by the symbol I, and its unit is the ampere (A). The current is the flow of electrons through a circuit.

...read more.

Middle

0.93

0.93

0.77

0.93

0.83

30cm

1.08

1.08

1.10

0.87

0.86

0.87

1.09

0.87

1.25

40cm

1.36

1.37

1.37

0.83

0.82

0.83

1.37

0.83

1.65

50cm

1.60

1.61

1.62

0.76

0.77

0.77

1.61

0.77

2.10

60cm

1.80

1.84

1.83

0.71

0.71

0.72

1.82

0.71

2.56

70cm

2.00

2.01

2.01

0.67

0.66

0.67

2.01

0.67

3.01

80cm

2.17

2.16

2.18

0.64

0.64

0.64

2.17

0.64

3.39

90cm

2.33

2.33

2.32

0.61

0.61

0.61

2.33

0.61

3.81

100cm

2.49

2.50

2.48

0.58

0.59

0.59

2.49

0.59

4.24

Preliminary investigation at 4.5V & 5.95A

10cm- 3A & 1.40V

100cm- 0.75A & 3.24V

Length of wire

Volt reading in Volts (V)

Amp reading in Amps (I)

Average reading

Resistance in Ω

...read more.

Conclusion

The procedure of the experiment was very good as it was very safe for my partners and myself. The wire was placed on a metre ruler so that you could measure the length of the wire easily. The experiment could have been improved by using digital ammeters so that you can get an accurate reading, the analogue ammeter could only read up to 1A, which meant that the ammeter couldn’t be used on an experiment checking the amp reading over 1A. Other than this I think that the experiment procedure was very good.

During the experiment I took down three readings for the voltage and amps from 10cm to 100cm. This made the evidence reliable because an average could be worked out from the readings. A problem with this was that the ammeter and the voltmeter was never still, it always changed from the first reading on the screen. The evidence was sufficient enough to support the conclusion, which proved my prediction right.

To make my work I could have added two ammeters on the circuit so that I could have got a more accurate reading, I could have also done the experiment on a longer wire I could have gone up to 300cm to see how the resistance is compared to the 100cm. This would have been a good experiment as light switches are sometimes a metre away from the light. Other then that the experiment was a good way to find out about resistance along a wire.

Bibliography

Physics a course for GCSE: Gilbert Rowell and Sidney Herbert

Modular Science for AQA: Keith Hirst, Mike Hiscook, David Sang and Martin Stirrup

NEAB Modular science: Richard Parsons

...read more.

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

See related essaysSee related essays

Related GCSE Electricity and Magnetism essays

  1. Peer reviewed

    Investigation in resistance in wires

    5 star(s)

    * The Voltmeter and Ammeter were also added. * The three lengths of wire were tested with 8 different voltages. Preliminary Results These are the results I collected in the preliminary test. Length of wire (Cm) Volts (V) Current (A)

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

    more collisions between the atoms and electrons which will then cause- the resistance to rise To rise. I cannot control this variable as it is very difficult and as I don't have the correct the equipment to do so but I can minimize the heating affect by doing preliminary results

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

    If the material has a high number of atoms or if there are more electrons in the outer shell or even if the atom is large (meaning that the electrons are weakly attached to the positive nucleus), the more electrons there are available.

  2. Discover the factors affecting resistance in a conductor.

    My scientific knowledge, as mentioned above, allowed me to conclude the best method to use. I have already concluded the control variables and dependant variables, so need a suitable method to fit them into my experiment. Scientific knowledge, such the ones shown below, helped me to decide what I should and should not change: i)

  1. relationship between voltage and current

    A good conductor is one that has low resistance. A good insulator has a very high resistance. At commonly encountered temperatures, silver is the best conductor and copper is the second best. Electric wires are usually made of copper, which is less expensive than silver.

  2. Finding a material's specific heat capacity

    The heating element and the conduction oil each have their own specific heat capacity and require energy to heat up and transfer energy into the copper block. As specific heat capacities change slightly with temperature, more minor errors could have been included in the calculated results.

  1. Resistance of wires

    for calculating electrical resistance, but still only applies to materials which comply with Ohm's Law (metals). Affecting Factors The four factors that affect the resistance of a wire are: * Material (the wire's material's construction and denseness affects the resistance of it, as, in this case, it depends how freely electrons can flow through it).

  2. Determining Voltage, Resistance and Current in a Parallel, Series and Series-Parallel Circuit.

    2 by attaching the red cable to red and black cable to black. 2. Measure the current in the series circuit by switching off and on the power supply and connecting the multimeter to the cables as show in the diagram below.

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