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

Internal resistance investigation - I will conduct the following investigation with the aim to find the internal resistance of a lemon battery, which I will construct myself.

Extracts from this document...


AS Physics – Internal resistance investigation

        I will conduct the following investigation with the aim to find the internal resistance of a lemon battery, which I will construct myself.

The variables that could affect my experiment are as follows:

  • Size of lemon – I will conduct my experiment in no longer than an hour, allowing me to use the same lemon for all results
  • Size of metal electrodes – I will use the exact same electrodes throughout the whole experiment
  • Length of any connecting wires – I will use the exact same wires throughout my experiment and will not break the circuit once I have started collecting data
  • Resistance in the circuit – I will vary this using a highly sensitive variable resistor as shown in my method.

To make my experiment fair I will only vary the most relevant variable to what I am investigating, which is the resistance in the circuit. All the other variables will be kept the same throughout the experiment as stated above.

        In my experiment I will need to measure the terminal pd, V, and the Current, I (in amps), for many values of resistance, R (in Ω), I will measure these as I know that V=E-Ir so these are the values that I need to know if I am to eventually calculate the batteries internal resistance. I think that to make my

...read more.


So the pd, V, available to the rest of the circuit is:

V = E – Ir

Where:        E = the e.m.f. of the cell

                I = the current through the cell

                And r = the value of the internal resistance

So Ir = the pd across the internal resistor

To find the internal resistance experimentally:

        As V = E – Ir, if you plot a graph of terminal pd, V, against current, I, the gradient of the graph will be equal to the internal resistance of the cell.

(From www.s-cool.co.uk/asphysics)

...read more.


        The only other problem I had with my experiment was the slight curve in my graph due to the deterioration of the battery as I was collecting my results. I could have avoided this by taking my results more quickly so the battery had less time to deteriorate and repeating the experiment more times to get a better average. This deterioration must have also greatly affected the margin of error in my experiment so I should have really thought about this more before I started taking my results.

        Because the battery deteriorates so quickly, this limits the amount of time that you can collect data without the results becoming more inaccurate, so repeating my experiment twice with the same lemon and electrodes probably also limited the accuracy of my experiment.

        Next time I would take more results more quickly and be more organised to make my results and conclusions more accurate. I could also investigate this topic further by using different substances for my electrolyte like different fruit juices or acids. I could also try using different materials for the electrodes and see how that affected the internal resistance

        I have completed my aim to find the internal resistance of my self-constructed lemon battery and found the internal resistance to be 5909.1 Ω.

...read more.

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. Marked by a teacher

    Internal Resistance of a cell

    5 star(s)

    Prediction measure Actual measure Identifying (a) Zero volts Zero volts This circuit is not intended when cells are in "series" or in "parallel" (b) 2.8 volts 2.9 volts This circuit is intended when cells are in "series" (C)

  2. In this experiment, we will measure the e.m.f. and the internal resistance of a ...

    equals the electromotive force and the gradient (m) is equal to the internal resistance r. Procedures 1. The switch was unplugged. 2. The rheostat was turned to the maximum value. 3. All the apparatus was connected as the above electric diagram. 4. The switch was plugged. 5. The readings of the voltmeter and the ammeter were recoded. 6.

  1. Investigating the E.m.f and Internal Resistance of 2 cells on different circuit Structures.

    and value for each circuit test * I will also use the same batteries throughout the investigation The following are variables that I will change: * the value of resistor in ohms will change in the circuit after it

  2. The aim of my investigation is to determine the specific heat capacity of aluminium.

    > Power pack > Polystyrene > Aluminium foil The errors caused by some of these apparatus are calculated later in this investigation. In order to calculate E, which is equal to ItV, I will measure the current (I) in amps with an ammeter connected in series, the voltage (V)

  1. Measuring the e.m.f. And Internal Resistance of a Cell

    I checked this and there was no error as far as I could see. * I may have taken too long to take the reading and allowed the cell to run down slightly each time. This would mean that the e.m.f.

  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. Design and Carry Out an experiment to determine the EMF and Internal Resistance of ...

    R and r are in series and given that the current flows through both, one after the other, their combined resistance can be written: E=IR + Ir or E=I(R + r) E cannot be directly measured because a voltmeter can only be connected across the entire cell, including the cells internal resistance, r.

  2. Free essay

    Finding the internal resistance of a solar cell

    result of the experiment at there level of sensitivity The temperature of the room in which the experiment takes place can affect the results of the experiment although are so minute that there are not worth trying to combat or account for.

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