00:01
Okay, so we have a circuit with an emf of 12 volts and a resistor that has a resistance of 4 .0 ohms.
00:14
It has a capacitor with a capacitance of 4 microfarads.
00:23
So we can also write that as 4 times 10 to the negative 6 farads.
00:28
And then it has a charge of 8 .0 microcoulombs.
00:38
So that's 8 .0 times 10 to the negative 6 coulombs.
00:45
And we want to know the current across the resistor when the switch is turned on.
00:53
So what we can do is use a couple of different equations here.
00:56
So the voltage across the capacitor is going to be q over the capacitance.
01:04
So the charge over the capacitance.
01:08
The current across the resistor, which is ultimately what we want, is the voltage across the resistor divided by the resistance.
01:19
So that's just using ohm's law.
01:22
And then we can find the voltage across the resistor by saying that it's going to be the emf minus the voltage across the capacitor.
01:33
So we can just plug in this first equation into this...