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

Investigate if the length and cross-sectional area affects resistance through a circuit.

Extracts from this document...

Introduction

PLAN FOR SCIENCE INVESTIGATION

Aim:

My aim is to investigate if the length and cross-sectional area affects resistance through a circuit.

Back ground scientific knowledge

What resistance is:image00.png

To find the resistance of something we use the following formula:  V

                              Resistance = V                                                    I    Rimage11.png

                                                    Iimage12.png

Resistance is the ratio of potential difference.

As long as I × V and the resistance is constant, and the conductor obeys Ohms Law.  The voltage increases, as long as they increase at the same rate.

 V

image13.png

image14.png

Constant

Temperature

image15.png

                                   I

Ohm’s law

Ohm’s law means that if the voltage is doubled, the current will be doubled. The formula for ohm’s law is the following:

V = I × R

This defines resistance, for Ohmic conductors the resistance is constant, and ohm’s law of proportionality holds.

What causes resistance is:

Resistance of a straight wire depends on:

  1. It’s length- the resistance increases with the increasing length.
  2. It’s thickness- the resistance is greater for thinner wires.
  3. It’s material- good conductors have a lower resistance.

...read more.

Middle

image01.pngimage09.pngimage01.pngimage08.pngimage01.pngimage01.pngimage07.pngimage01.pngimage03.pngimage01.pngimage03.pngimage01.pngimage02.pngimage10.pngimage01.png

image01.png

                                                                                          = Atoms vibrating

Electrons move around the lattice in a random movement, with different speeds and different directions.  They collide with each

Other and the atoms. As they hit into each other the movement is passed on and the vibration increases.  More collisions mean greater resistance and more energy exchange.

Variables

Length: The longer the piece of wire the more collisions there is, and therefore the greater the resistance for a given current.

Cross-sectional area: The narrower the conductor the greater the number of collisions for a given current.

Temperature: the higher the temperature the more vibration in the lattice, the more collisions for a given current.

Material: the material from which the wire is made.

Resistively: resistively is related to the number of factors, which

affect resistance:

  • Number of free electrons
  • Crystallinity in lattice

By reducing crystallinity, it quickens up the flow of electrons and increases collisions, for a given current.

Preliminary work

To help me understand more I have decided to do some preliminary work.  This will help me to research the experiment and explore faults in the experiment.

...read more.

Conclusion

Conclusion

My graphs show that there is a relationship between my voltage and current.  I can see that my results form a straight-line graph, which shows that my results are correct. I can also say that my choice of equipment was correct as I obtained good results. I controlled the variables well throughout the experiment, particularly the temperature.  I did this by switching off the D.C power supply after each result, to keep the temperature down.  I have discovered that the smaller the CSA of the constantan wires, the lower the resistance. I have observed the relationship between voltage, current, and gradient.  The higher the gradient the greater the resistance, which means there must be an increasing voltage and current.  My graph shows that it obeys ohms law, and did not over heat.  Overall it showed to be a success because I obtained a straight-line graph.

...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. How the Resistance of a Wire is affected by Cross-Sectional Area

    what the results show, and it proves that my prediction was correct. Evaluation I think that the experiment was also quite successful and the results were reasonably accurate, apart from some anomalies which are circled on the graphs, the anomaly in experiment one was far off the line of best

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

    that drift to the positive end and by absorbing electrons at the positive end. Although the two terminals (positive and negative) are constantly receiving and sending out electrons, the electrons themselves do not move very quickly. It is the current that flows through the electrons at the speed of light

  1. My aim is to find out how different cross sectional areas of a wire ...

    Resistance is caused when these electrons flowing towards the positive end have to jump atoms. The more difficult it is for the electrons to move the higher the resistance. So the larger the cross sectional area the larger the space for the electrons to move about in meaning not a

  2. How does the length and cross-sectional area of a wire affect resistance

    Due to this the length increase should be proportional to the resistance increase. Figure 2 The wire above is half the length of the wire in figure 2 and so there should be half the number of collisions between the electrons and the atoms.

  1. Physical - Circuit

    First Tried Second Tried Third Tried Length (centimetres) Voltage (Volts) Current (amps) Voltage (Volts) Current (amps) Voltage (Volts) Current (amps) 5 0.2 3.5 0.1 2 0.1 2.1 10 0.2 1.8 0.1 1.8 0.1 1.8 15 0.2 1.8 0.1 1.75 0.2 1.75 20 0.25 1.7 0.25 1.8 0.2 1.7 25 0.3 1.7 0.3 1.7 0.3 1.7 30 0.4 1.7 0.35 1.7 0.35 1.7 Length (centimetres)

  2. AimTo investigate the variables that affect resistance in an electric circuit.

    The standard abbreviation for electric resistance is R and the symbol for ohms in electric circuits is the Greek letter omega, U. For certain electrical calculations it is convenient to employ the reciprocal of resistance, 1/R, which is termed conductance, G.

  1. Investigate how the cross-sectional area of a piece of wire affects its resistance.

    This would cause our results to turn out inaccurate, and our experiment would not be a fair test. To solve this problem, we will increase the length of the wire to 1.0m, but to ensure the experiment was completely fair we will add a switch into our circuit, to make sure the wire will stay cool.

  2. Investigate how the cross section of a wire affects the resistance in a circuit.

    3. Cross Section- My prediction is that the bigger the cross section is, the less resistance will be produced. 4. Material- The material used for the wire is a very important factor that has to be taken in account for, because the resistance of a wire depends on the factor called resistivity.

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