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

To investigate the resistance of different materials in the form of wirer, resistors and other materials.

Extracts from this document...

Introduction

Ohms Law Planning A: Aim: To investigate the resistance of different materials in the form of wirer, resistors and other materials. Hypothesis: The shape, the thickness, the length of the resistor and the material that makes up the resistor itself will affect the electric conduction capability (resistance). Electrons can create a current, so the more free electrons there are, the more conducting capability that material has that is why metals conduct. Materials with wider diameter have more free electrons because the surface area is bigger compared to length so more electrons are free per cm as example. So if a cable is bigger in diameter it should have less resistance. Resistance will also increase as the length of the wire increases because electrons will be slowed down while traveling. ...read more.

Middle

* Resistor Method: * Connect the wires to the circuit by the crocodile clips * Take the voltage and current readings from the meters * Increase/decrease the supply from the power pack and take the readings again * Repeat the experiment with different materials, wires, bulbs, resistors Results: Wire: Setting Volt Actual Volt Ampere Milliampere Resistance Ohms 2,00 1,80 0,100 100,00 18,00 4,00 3,50 0,200 200,00 17,50 6,00 5,50 0,300 300,00 18,33 8,00 7,50 0,420 420,00 17,86 10,00 9,30 0,520 520,00 17,88 12,00 11,40 0,600 600,00 19,00 Average: 18,10 ? Bulb (variable resistor used): Actual V Ampere Milliampere Resistance Ohms 1,40 0,12 120,00 11,67 1,70 0,14 140,00 12,14 1,80 0,14 140,00 12,86 2,60 0,15 150,00 17,33 3,50 0,16 160,00 21,88 4,40 0,18 180,00 24,44 5,50 0,28 280,00 19,64 7,50 0,32 320,00 23,44 Average: 17,92? ...read more.

Conclusion

Here the current and voltage are not proportional. The bulb obviously gets hotter and hotter. Since "resistance" is measured by the gradient of the graph, we have here an example where the resistance is increasing. But obviously we are dealing with "normal" resistors in this investigation, so the gradient of the graphs obtained should be the same throughout linear and the resistance should remain constant as the voltage/current is changed. Evaluation: * To get better results the following things should be done: * The power supply should be varied smoothly between 0-12V with 0.1V interval so more averaged results can be taken. * Temperature has to be absolute constant to create a fair test. Otherwise Ohms law will not apply. * Better quality equipments should be used. * More accurate Meters Philipp C. Protschka Page 1 of 6 1 May 2007 Physics Practical Last printed 12/3/2002 12:16 AM ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our AS and A Level Electrical & Thermal Physics 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 AS and A Level Electrical & Thermal Physics essays

  1. To Investigate How the Resistance of the Light Dependent Resistor Depends On the Current ...

    When the current of the light bulb increases form 27.5 MA to 60 MA, the resistance of the LDR decrease as well, so the current increase. Evaluation From my results table and graph, I can see that my results that I collected are quite reliable and accurate.

  2. Investigating the effect of 'length' on the resistance of a wire

    Gradient = 54.84 ?/m If we re-arrange the resistivity formula we will see that: Resistance = R e s i s t i v i t y Length Cross-sectional area Anomalous Results From The Graph Of Average Results: From my results, I can prove the uncertainty by making use of the resistance formula.

  1. Investigating how temperature affects the resistance in a wire

    Fair test/reliable results: To ensure that this experiment produces reliable results and be a fair test, any factors, which can affect the experiment, are controlled (see above) and any measurements are taking to the highest degree of accuracy possible. To help produce accurate results, the experiment is repeated twice so

  2. Find The Internal Resistance Of A Power Supply

    equipment which could damage the circuit and cause the fuse to blow. The work surface will be cleared of clutter before beginning experiment to make sure that the equipment is stable. When connecting and disconnecting equipment, I will turn of the power pack to avoid electrocution.

  1. Resistor - What do resistors do?

    Carbon film resistors are cheap and easily available, with values within �10% or �5% of their marked, or 'nominal' value. Metal film and metal oxide resistors are made in a similar way, but can be made more accurately to within �2% or �1% of their nominal value.

  2. To investigate the factors which may affect the resistance of resistance putty.

    To calculate resistance, one needs to know the current reading (in Amperes) and the potential difference over the object we are trying to find the resistance of (measured in volts). To work out the resistance from these two values, the formula: - V = R (i.e. Potential Difference = Resistance)

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