00:01
For question 1, how fast does the current through it change when the voltage is 10 volts? in an inductor, v is equal to l times d -i -d -t.
00:10
So how fast it changes is d -i -d -t, and that's equal to our voltage divided by l, which is 10 divided by 5, and we get 4 amps per second.
00:21
For question 2, we want to find how much energy is stored.
00:25
So our energy is 1 -5 times l -i -squared, and at this instant, we have 1 -5, times 0 .80 times 1 .2 squared, which is 0 .576 joules.
00:37
For question 3, at what time is the current equal to 0 .40 amps? so the time constant, z, is equal to l divided by r.
00:46
So let's note that down.
00:49
The current through any time through an inductor is i .0 to the negative t over z.
00:54
So we have 0 .40 is equal to 1 .2 e to the negative t divided by z...