2. Methods

Method – Description in detail of method or procedures (The following are important and key items that should be included when formulating ANY AND ALL research plans.)

Equipment list:
  • Six LEDs emitting coloured light – one each of red, orange, green, blue, and yellow. Choose LEDs with a clear, colourless casing surrounding the LED, so that the colour of the light comes from the device itself, not from the coloured casing.
  • Four 9 V batteries
  • Two multimeters (one to be used as a voltmeter and the other as an ammeter)
  • 1 kΩ potentiometer or rheostat.
  • Six Alligator clip Wires
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Procedures: Detail all procedures and experimental design to be used for data collection
  1. Connect the ammeter in series with the LED to measure the current through it, and connect the voltmeter in parallel to the LED to measure the voltage across it. The applied voltage can be changed by using the potentiometer or rheostat.

  1. Change the voltage in steps of 0.05 V from 0 V to 3 V and measure the resulting electrical current. Note that when the current flowing through the LED is small, the LED might not light up, but the ammeter can still measure the current. To protect the LED, take note to keep the current below 5ma

  1. Repeat experiment for each LED twice to calculate average.

  1. For each LED, plot a graph of current against voltage. On each graph, find the straight line of ‘best fit’ to join up the points that slope up from the x-axis. If the points lie close to the line, this shows that a linear relationship holds between the applied voltage and the current in this region of the graph.

  1. Finally, determine the activation voltage (Va) from the collected data. This is the point at which the current begins to increase linearly with voltage. It can be read off the graph by extrapolating the straight line representing the linear response region backwards

    Risk, Assessment and Management: Identify any potential risks and safety precautions to be taken.

    Risk Assessment Management

    Risk chance
    Shocked by the electricity
    Don’t touch the wires when electricity is transmitting
    LED lights shine in your eyes, causing temporary blindness
    Don’t stand in front of the LEDs
    Breakage of glass covering LED, cutting yourself on the glass shards
    Be careful not to drop the LED or hold it with a lot of force
    Burnt by Heat from battery
    Do not touch battery when in use

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