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

Experimental Verification of Ohm's Law

Extracts from this document...

Introduction

Experimental Verification of Ohm’s Law

Apparatus

  • E.M.F Source – Battery of 2 X 1.5V Cells
  • Battery Holder
  • Switch
  • Variable Resistor (Rheostat)
  • Ammeter (preferably digital)
  • Voltmeter (preferably digital)
  • Sample of conductor to be tested (Nichrome wire) – 10cm
  • Connecting Wires
  • Crocodile Clips

Procedure:

  • Choose the ranges of the ammeter and the voltmeter to suit the particular conductor to be tested. (e.g. 0-2V and 0-1A)
  • Set up the circuit as shown above.
  • Make sure that the voltmeter is connected in parallel across and the ammeter is connected in series with the conductor.
  • Ammeters and Voltmeters have terminals marked + and – which must be connected correctly to the battery. Only close the switch when you are sure that you have wired the circuit properly.
  • Close the switch and smoothly adjust the rheostat from minimum resistance to maximum resistance and at regular intervals note the meter reading and hence obtain a set of values from the two meters (at least 6).
  • Divide the Voltage by the current to get Resistance and tabulate the results in a table as shown below
...read more.

Middle

Current Reading 3

Voltage Reading 3

Current/ Voltage

Current Reading 4

Voltage Reading 4

Current/ Voltage

Current Reading 5

Voltage Reading 5

Current/ Voltage

Current Reading 6

Voltage Reading 6

Current/ Voltage

Graph the results using a suitable scale. Have Voltage on the X-Axis and the Current on the Y-Axis and draw a line of best fit as shown below.  You can calculate the resistance using the gradient of the line which should pass through the origin showing the relationship that Voltage is directly proportional to Current and the constant of proportionality is the resistance of the conductor.

image00.png

Results Obtained

...read more.

Conclusion

To reduce the sources of error, a umber of measures can be taken. Firstly, the switch should not be closed until you are absolutely ready to start the experiment and take the readings straight away. Also, the temperature of the wire should be checked before the experiment to ensure that it is at normal temperature.

Also, we could immerse the nichrome wire in a beaker of water to ensure that its temperature remains constant throughout the experiment and does not increase with an increase in resistance. We could also disconnect the wire from the circuit after taking every reading and allow it to cool down before taking the next reading.

Also, we could repeat the experiment for accuracy and we could also use other conductors of slightly less resistivity such as copper to prevent the temperature from increasing so quickly.

...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

Here's what a teacher thought of this essay

3 star(s)

This is a brief report that has an appropriate structure but is incomplete.
1. The report is missing several sections, such as an aim, hypothesis and variables section.
2. The conclusion should quote data to back up the patterns.
3. The evaluation is missing a subheading and should suggest further research opportunities.
***

Marked by teacher Luke Smithen 13/08/2013

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. Marked by a teacher

    The factors affecting the resistance of a metalic conductor.

    4 star(s)

    If this is carried out over a larger distance there will be more atoms for the electrons to hit. Therefore resistance is proportional to the length of the conductor, providing the temperature, cross sectional area and material of the conductor are kept constant.

  2. Peer reviewed

    resistance of a wire

    3 star(s)

    I can also change the length of the wire. The other alternative that I had was the thickness of the wire. This option was too hard as it was difficult to measure the thickness of the wire. Plan In this investigation I plan to investigate how the length of an 18SWG constantan wire affects the resistivity of the circuit.

  1. An Experiment to test which combinations of metals will produce the highest voltage in ...

    If the anode was zinc (-0.76) then the difference would be 1.1 - not as large a difference as the magnesium due to it being less reactive. Other examples could be zinc and magnesium, a difference of 1.61, lead (-0.13) and iron (0.04), a difference of 17 and so on.

  2. Factors affecting Resistance of a wire

    Move the crocodile clip to 20cm. Make sure the teeth of the clip are firmly on the wire. Turn on the power supply to 3V. Take readings from the voltmeter and ammeter. Turn off the power supply and repeat this paragraph again with 6V and 9V.

  1. The Bouncing Ball Experiment

    Aim/Method of Preliminary Experiment: For my preliminary experiment, the ping-pong ball was dropped from three different heights. It was dropped from heights of 100cm, 200cm and 300cm from a measured distance up a staircase. Each reading was repeated three times and an average bounce height was found for each height.

  2. Design an experiment to predict and test the output from a simple AC generator.

    This makes the lower end of the wire negatively charged and the upper end electron deficient, or positively charged. As the wire is in a circuit this set's up a current and an emf is induced into the wire this current flows from the upper end of the wire to

  1. Resistivity in a wire coursework

    there is likely to be more collisions in a longer wire because there will be more ions. Metals contain a large number of free electrons. As these free electrons move through the wire, they collide with metal ions that are vibrating.

  2. Determining Voltage, Resistance and Current in a Parallel, Series and Series-Parallel Circuit.

    (Note: make sure the multimeter is set to 200mA) Macintosh HD:Users:TrixSwift:Desktop:Screen Shot 2013-10-20 at 6.22.52 PM.png Parallel Circuit 1. Connect the bulbs together with the wire as shown in the diagram below Macintosh HD:Users:TrixSwift:Desktop:Screen Shot 2013-10-20 at 6.24.56 PM.png 1. Using the multimeter measure the resistance of each bulb. 2.

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