Can you please explain why the answer is C to question 20
This is because the current is at first higher as the capacitor allows a high current. However as the capacitor charges the current that can flow through a capacitor decreases. http://revisionworld.com/sites/revisionworld.com/files/imce/charging-a-capacitor.gif
Since the capacitor is replacing a resistor this means that the current initially rises before it then falls. I hope this is helpful.
Thanks Thomas, that’s absolutely right.
To add to this answer you can also say that initially the charge across the capacitor is 0, so the voltage across the capacitor is zero (because Q = VC). Previously the voltage across the (swapped out) resistor was greater than zero, so the voltage across the remaining resistor must have increased, and therefore the current has increased. As time goes by the voltage across the capacitor increases, and at some point this means that the voltage across the remaining resistor falls below the initial voltage and thus the current falls below the initial current.
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