**1. The problem statement, all variables and given/known data**

Hey guys, I have a physics II test tomorrow on Electricity and Magnetism, and I cannot seem to figure out this question.

The rectangular loop in the figure has 2.2×10−2Ω resistance.

What is the induced current in the loop at this instant?

Picture:

**2. Relevant equations**

E = d(flux m)/dt

B = (mu_0)(I)/2(pi)(r)

flux m = integral (B * DA)

**3. The attempt at a solution**

However, the area is not changing, so I can pull that out of the integral.

Then I have to integrate:

(mu_not)(I)/2(pi)(r)

Everything is constant except 1/r, so I can pull everything out and be left with:

integral (1/r)dr = ln(r)

So now we have:

E = d/dt(A)*(mu_not*I)*(ln(r))/(2*pi)

How do I take the derivative of this with respect to time?

Did I do the other steps correctly?

http://ift.tt/1lLUsCy