• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12

Resistance of a Wire

Extracts from this document...


Physics Investigation: Resistance of a Wire

I have been asked to solve the problem of getting a resistance of 1.9 ohms using resistance wire. Resistance is how easily a potential difference is carried across a conductor. The higher the resistance, the bigger the potential difference has to be to go through the conductor. To do and understand this investigation I must see firstly what factors are involved when looking at resistance. I have come up with six things which affect the resistance in a wire:-


If the wire is very thick i.e. it has a big cross sectional area (csa). It will have a smaller resistance than one with a smaller csa. This is because electric current in a metal is made up of electrons jumping and hitting more electrons, like dominoes. The metal ions in the wire block some electrons, causing a resistance. If there is a bigger area through which the electrons have to squeeze, the resistance will evidently be lower.

Material of Wire-

This is quite an obvious one, as I know that all materials have different conductivity. For example copper is a better conductor than tungsten but silver is the best. By knowing what the conductivity of a material is, I know how much resistance it would have, as the better the conductor the less the resistance.


...read more.









There should be 3 such tables, and one with just the average resistance and length.

Length (cm)

Average resistance (Ohms)

I know of the link between potential difference, current and resistance. It can be written in the form

R = V/I. This is the equation I must use to find the resistance for my results. As I have said above, I think there should be a direct link between resistance and length. I know there should be a basic link because of the electrons that make up an electrical current. They have to get past the ions in the metal, and the longer the wire is, the more ions there are, so the bigger the resistance is against them. I also think there will me more of a direct link between length and resistance. I can show why I think this using my scientific knowledge:

        Resistance = conductivity X length / cross-sectional area

In my experiment the conductivity will always be the same, as I will only use one type and material of wire. Also, since I am using one type of wire, the cross sectional area will remain constant. Therefore I can rewrite the above equation as:

        Resistance = k X length (where k is a constant) or R      L

I can replace the conductivity and the cross-sectional area because they will remain the same.

...read more.


        Apart from this error, I did not find anything else significantly wiring with my experiment. There was, however, one strange result. In my graph, I drew the line of best fit to fit as many points as I could while still going through the origin, but there is one point which didn’t fit. This could just have been my line, maybe the results weren’t accurate enough to go through the origin. Or it could have been that my measuring was not accurate enough first time; that I didn’t measure 10cm exactly enough and so came up with an anomalous result. To overcome this I could haven used a more exact ruler. However I think that my results are accurate and reliable enough to support my conclusion.

        One way to further this investigation would be to see how the width of the wire affects my formula. I think that as the width got smaller, the resistance would increase. This would be because of the original formula Resistance = conductivity X length / cross-sectional area. As the width got smaller, cross-sectional area would get smaller, and by dividing by a smaller number would give a bigger resistance.

GCSE Physics Investigation

The Electrician’s Dilemma

...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. Strain Gauge

    I'm using 1m of very fine wire so I can measure the strain on the wire more accurately. I found the best way to attach the fine wire to the circuit was to use crocodile clips rather than rapping it round.

  2. To investigate how the length (mm) and the cross-sectional (mm2) area of a wire ...

    Now that I know the density and mass of the wire, I can calculate its volume using Volume = Mass/Density. Once the volume is calculated, I can easily calculate the cross-sectional area of the wire by dividing the volume by the length of the wire.

  1. Super Conductivity

    The process of the flow of electrical energy in an electrical conductor as described here in the "Aumic" Theory , illustrates without any anomalies every phenomenon associated with super conductivity.

  2. The Electrician's dilemma.

    Resistivity = ?m Constantan is a high resistance alloy of approximately 60% Copper and 40% Nickel, With a very low co-efficient of thermal expansion ( measure of expansion on heating). It is used widely in electrical resistors. What is resistance?

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