00:01
For part a, we'd like to calculate the value of the current i -1.
00:07
So for our current, we can set up a ratio for a current of i -1, and it's going to be equal to our magnetic fields due to i -2.
00:18
We have mu -not i -1 divided by 2 -r1, equal to mu -not i -2 divided by 2 -r2.
00:27
So from this expression, we see that i -1 is equal to i -2 over r2 times r1, where r1 is equal to our d, which is 12 .9 centimeters, plus 4 .98 centimeters to the right.
00:44
So let's plug that into a calculator.
00:47
12 .9 plus 4 .98.
00:51
That's equal to 17 .8 centimeters.
00:56
And what is our r2? our r2 is just at 4 .98 centimeters a given energy.
01:06
Our problem.
01:09
Okay.
01:10
So i -1, as we saw, is equal to this.
01:14
So i -1 is equal to our 10 .7 divided by 17 .8, or this should be divided by r2, which is 4 .98, times 17 .8 centimeters.
01:31
Now let's plug that into a calculator.
01:34
10 .7 divided by 4 .98 times 17 .8, which is 30 .7 .8, which is 30 .7 .7, divided by 4 .98, 0 .2 amps.
01:45
Now we also have a question b.
01:48
Question b asks us to find the magnitude of the magnetic field at point a...