Data Analysis:
The result of this experiment is shown as below:
Discussion:
When the capacitor is being charged up, the microammeter reading decrease with time, and the CRO trace reading increase constantly. Since the current should be kept in a steady rate in order to make a fair test, so we have to adjust the amount of current for the sake of keeping the current in uniform.
Also, form the result shown above, we will investigate how the charge on a capacitor is related to the p.d. applied across it by charging the capacitor at a constant rate, so , we will plot a graph of p.d. across the capacitor against time.
The graph is shown on the next page.
The graph of p.d. across the capacitor against time:
From the graph, we can know that p.d. is directly proportional to the time, which means when the time is increase, the p.d. across the capacitor increase also.
And also, from the theory, if a capacitor is charged up at a constant rate, i.e.=I, where I is a constant. Then= is also a constant. Hence, we can deduce that the potential difference across the capacitor increases linearly with time.
Error analysis:
~ There will be systematic errors like there are zero errors of the microammeter so that we cannot keep the current in a steady condition.
~Also, there will be random errors which produce unpredictable deviations from the true value. For instance, there are human reaction time, random parallax error and imperfect material used.
Possible improvements of the experiment:
~ Since the systematic error cannot be reduced or eliminated by taking the average of repeated readings, so, we should tackle the problems by techniques such as calibration curves and control experiment.
~ Moreover, random error cannot be eliminated but could be reduced by taking the average of repeated reading.
