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# Capacitance help Watch

1. Im quite confused on this question. It says that the capacitance is constant. Using E = 1/2 x VIt i realised the gradient is Vi/2 so since the current in the capacitor is falling that means the gradient is falling yes? So the answer is A. But in my text book V is 0 at time = 0 while current is maximum? But this was with a resistor.The circuit doesnt have a resistor so does that mean V is constant? Can someone explain why the gradient is decreasing please

Thank you
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2. e is proprtional to v from e=qv. When charging a a capacitor, electrons arrive at a plate and cause that plate to become negative. This pushes electrons away at the other plate. A capacitor charges until it has the same potential difference across its plates as the supply. Then as electrons try to go to the first plate, there is such a massive build up of negative charge that the are repelled and the capacitor can no longer charge which is why the voltage gradient gradually decreases and levels out

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Updated: April 16, 2014
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