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

Resistance of a wire.

Extracts from this document...

Introduction

Physics AT1, Resistance of a wire.

Plan:

Current

Electric current, the flow of electric charge, usually in the form of electrons. In a circuit, it is measured using an ammeter, and the SI unit of measurement is the ampere (A). It may be direct current (D.C.), in which case the charge flow is one way, as from a battery. Or it may be alternating current (a.c.), as from a mains supply. Here, the charge flows alternately backwards then forwards in a circuit many times every second. The equation for current is I=Q/T; A=C/S; current= charge/time.

Resistance

Resistance, the ratio of the potential difference (p.d. or voltage) across a conductor to the electrical current which flows through it as a result. The unit of measurement is the ohm (O), this being the resistance of a conductor requiring a potential difference of 1 volt across its ends to produce a current of 1 ampere. For a given metal conductor at constant temperature the value is the same whatever the current (Ohm's law), but rises if the temperature rises the equation for Ohms law is V=IR; Voltage (p.d.) =current x resistance. Any conductor possessing resistance gives off heat when a current flows through it.

...read more.

Middle

Voltage (V)

Resistance (Ω)

100

10

Length (cm)

Average Current (A)

Average Voltage (V)

Average Resistance (Ω)

100

0.10

2.53

25.3

10

1.05

2.00

1.9

Apparatus:

  • 100 cm of constantan wire
  • Voltmeter
  • Ammeter
  • Crocodile clips
  • Leads
  • Power pack
  • Meter rule

Diagram:

Method:

  1. I will measure out 100 cm of the constantan wire
  2. I will set up the apparatus as in the diagram
  3. I will take three readings from the ammeter and the voltmeter and the voltage of the power pack will be at 5 volts
  4. Repeat at
  • 90 cm
  • 80 cm
  • 70 cm
  • 60 cm
  • 50 cm
  • 40 cm
  • 30 cm
  • 20 cm and
  • 10 cm

Safety:

Before starting the experiment I will test all the equipment to make sure that all the equipment is not faulty. I will also do the experiment at a safe voltage. During the experiment I will turn the power pack on then quickly take a reading then switch it off.

Fair testing:

...read more.

Conclusion

The results that I have obtained support my original prediction. This is because in the prediction I said that as the wire length increased, the resistance should increase. I also said that the link should be directly proportional. The results have shown that this is true.

The line of best fit clearly shows that the results followed the expected pattern very well. The points are very close if not touching the line. This shows how the results were directly proportional through out, as the gradient remained the same.

Evaluation:

I think that my investigation was performed to a fairly high standard and good quality. I think that if I were to investigate another factor as well as the length, this investigation would have been improved by quite a lot. Also I feel that if I were to investigate the different types wires and their resistance in conjunction with the length, this piece of coursework would have been of an extremely high standard and of an excellent quality.  

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

    All metals are good conductors, because they have many free electrons that can move in-between the atoms, and so therefore a current will flow. A good conductor has a low resistance and a poor conductor has a high resistance. Thin wire within a lamp will resist the movement of electrons that is within it.

  2. Investigating The Characteristics Of A Filament Lamp

    However, if the graphs begin to show the shape of the filament lamp graph, yet do not fully show the shape, the investigation could be extended by taking more recordings, and drawing a new graph. The investigation could be extended further by using the same circuit to investigate a different

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