The aim of my investigation is to investigate how the brightness (intensity) of light shining on the LDR (Light Dependant Resistor) affects the Resistance.

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The aim of my investigation is to investigate how the brightness (intensity) of light shining on the LDR (Light Dependant Resistor) affects the Resistance.

We can change the intensity using different methods. One method is to increase the voltage, by plugging the power supply to a higher voltage. But this method can be hard as you might not be able to know how higher the voltage is, it might be harder to have access to higher voltage, as it is dangerous.

Another way is to change the brightness by adjusting the power supply. Also the distance between the bulb and the LDR is another method, if the distance is bigger, the less bright it would be. If the distance is less/smaller, the denser it will be.

We could also use different bulbs and power supply, with a higher voltage and energy, the higher the voltage, the brighter the light bulb. But this may be hard, as we might not have many different power supplies or bulbs. I could also put different densities of filter between the bulb and LDR. The last method that I could use is to use different sizes of the apertures used in the experiment. If an aperture is more open, then more light will flow through, but if the aperture is more closed then light will hardly pass through.

I am going to use the method of changing the distance, because this is the easiest method to carry out. Also the results from this method of experiment would be more accurate as it is easy to record the results through this method.

We will send the current through the LDR; a Voltmeter/Ammeter will measure the current.

The measurement unit ‘Amps’ (A) is not sensitive enough to measure smaller current; therefore we measured the current in ‘Milliamps’ (MA).

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From my Preliminary Study, I have discovered the appropriate distances that I will use in my final experiment.

As there will be 5 readings, there will be 5 different distances. 0cm will not be one of the distances because the LDR can't be put in to the Bulb.

We will keep small distances because of the external light entering from the windows of the classroom. The more the distance, the more external light will interfere. However we must have external light for safety reasons. Without external light, accidents could occur, which could result in bulbs or anything ...

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