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

The aim of this investigation is to find out if length will affect the resistance of a wire in an electrical circuit.

Extracts from this document...


Physics Sc1


The aim of this investigation is to find out if length will affect the resistance of a wire in an electrical circuit. Hopefully my research will be proven by the experiment.

Preliminary work

From research I discovered that resistance occurs when the charge carrying particles, called electrons travel along the wire and collide with atoms or other electrons in the wire. This causes resistance so the molecular structure of the wire determines the number of collisions, therefore level of resistance. I also found out in my research that if the wire is heated the resistance will increase. If the wire length decreases the resistance will also decrease. This is because the electrons have less wire.

We made sure the experiment was safe and a fair test by switching off the current between readings to prevent overheating, which could increase the risk of burns, as well as make the results inaccurate.

...read more.


Increase voltage noting ammeter reading and observing wire.Repeat above


As the current increases the wire gets hotter until it melts.


There is a heating effect. Fuses work by melting if the current is too great.


From my research I can predict that if I increase the length the resistance will increase, this is because the length and resistance are directly proportional. If I increase the length by 10cm the resistance will increase by about 0.5Ω.

If I double the length the resistance should double and if the voltage doubles the current should double as well.


  • Ammeter.
  • Voltmeter.
  • Crocodile clips.
  • Metre ruler.
  • Power pack
  • Wires.
  • Wire




  1. Set up equipment, as shown in the diagram.
  2. Use metre ruler to measure 50cm of wire, and attach the crocodile clips.
  3. Switch on power pack, use variable resistor to get 1v on voltmeter.
  4. Take reading from the ammeter, and then switch the power pack off to let the wire cool down.
  5. Repeat step 4 for lengths 60cm, 70cm and 80cm.


...read more.


The experiment sort of, followed Ohm’s Law. It didn’t quite follow Ohm’s Law exactly because Ohm’s Law is only correct if the temperature stays the same.

Most of the points plotted on my graph are close to the line of best fit.  This means the experiment was carried out well.

I have one anomalous result; the other results are very close to the line of best fit on the graph so must be quite accurate. The reason I have this anomalous results is due to change in temperature while completing the experiment.

I believe that I have gathered enough evidence to support my conclusion; I repeated the experiment three times for each different length to make sure and get an accurate average resistance.


  • I could have kept the temperature constant, and made sure of this, by keeping the length of wire in a water bath at a constant temperature.





...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. An investigation to find out how the electrical resistance of a wire changes in ...

    In fact resistance, in ohms(R) is equal to the potential difference, in volts (V) divided by the current, in amperes (I) - Ohm's law. This can be shown in this equation: R = V This equation can be rearranged to show that current depends on resistance when P.D.

  2. Resistance of a Wire Investigation

    The more spread out the light is, the less intense it is, and so moving a lamp closer to the elodea increased the light intensity. To ensure I obtained an accurate set of results, I did the experiment three times and found the average.

  1. Investigating The Effect Of Resistance On A Capacitor Circuit

    2.728 8 0 0.014 1.42 1.95 2.671 8.5 0 0.007 1.3 1.858 2.615 9 0 0.007 1.194 1.774 2.558 9.5 0 0.007 1.088 1.696 2.502 10 0 0 1.003 1.618 2.445 10.5 0 0 0.919 1.548 2.388 11 0 0 0.848 1.477 2.339 11.5 0 0 0.777 1.413 2.29 12

  2. An Investigation into the factors that affect the electrical resistance of a wire

    To ensure that the experiment is as accurate as possible, the lengths of wire must be measured from the inside of the crocodile clips, and the wire must be held straight when conducting the experiment. Any bends or twists in the wire may result in a short circuit or affect the resistance so that the readings would not be accurate.

  1. Physical - Circuit

    Table 5: This table shows the details about normal wires used in the experiment, Constantan wire with diameter of 0.90mm, however is longer than the one before, retry. First Tried Second Tried Third Tried Length (centimetres) Voltage (Volts) Current (amps)

  2. In this investigation I will aim to determine what affect a greater length of ...

    > Measure length of first wire to be 10cm. > Take 5 readings of voltage and current. > Then repeat experiment, with increasing the length of wire by approximately 10 cm each time. Repeat until you get up to 100cm Fair test: To keep this a fair test there are

  1. Investigating Resistance in an electrical circuit

    For my experiment I have decided that I will see whether the length of wire affects the resistance in a wire and I have also decided to see whether the thickness of the wire will also affect the resistance in a wire.

  2. Investigate how the electrical resistance of a wire changes in relationship to it's length.

    Length (cm) Current (A) Voltage (V) Resistance (=V/I in �) 10 0.3 0.13 0.43 15 0.3 0.20 0.66 20 0.3 0.28 0.93 25 0.3 0.34 1.13 30 0.3 0.40 1.33 35 0.3 0.48 1.60 40 0.3 0.57 1.90 45 0.3 0.62 2.06 50 0.3 0.70 2.33 Average Length (cm) Resistance (�)-Set (i)

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