00:03
At this problem, we have two coils wrapped around the same cylinder.
00:07
On this drawing, i have one of those coils in red, the other in black.
00:11
And for the first part, we're trying to find the mutual inductance when the rate of change in the first current is 0 .242 amps per second, and the induced emf in the second coil is 1 .65 millerbolts.
00:25
So to do this, we need to recall that the induced emf in the second coil is given by the mutual inductance, multiplied by the rate of change in the first current.
00:39
With this, we can just rearrange that, and we have the mutual inductance being the emf in the second coil, divided by the rate of change in the current of the first coil.
00:52
And we have both of those, so we have 1 .65 millivolts, and we are told that is 0 .242 amps per second.
01:04
And if we plug that in, we get 6 .82 times 10 to the negative 3 henrys or 6 .82 million henries.
01:21
For the second part, we want to find the average flux through each turn in the second coil when there are 25 turns in that second coil and the current in the first coil is 1 .20 amps.
01:34
So to do this, we can recall that the mutual inductance is also given by the total flux through the second coil over the current in the first coil.
01:50
And if we solve for the flux in this equation, we have that as m -i -1 over n2...