00:01
So for this question, we are looking at a circuit that is charging a capacitor.
00:10
And this is when the switch is in position a.
00:15
And when it's fully charged, when it says that it has been the position for a very long time, it means that the capacitor must be fully charged.
00:28
And what it means by fully charged is that the potential across the capacitor must be the same as the emff of our battery, which in this case is 9 volts.
00:40
So we can actually find the charge.
00:45
On the capacitor, using equation c times v.
00:54
This is equals to 9 volts times.
01:00
Capacetons is given as 4 microferons.
01:04
So this gives us 36 microcuroats.
01:11
To find the current immediately after the switch is changed.
01:19
We'll make use of the fact that the capacitance act like a battery when it is just switched over with an emf of about 9 volts.
01:33
So we can use that to find the current, r equals to v over r.
01:37
The v is provided by the capacitor, which is 9 volts, and the r is the resistance of the resistor.
01:42
Given as 25...