# Solenoid physics homework

1. Apr 25, 2008

### Snazzy

1. The problem statement, all variables and given/known data
A small 2.0-mm-diameter circular loop with R = 0.020 Ohms is at the center of a large 100-mm-diameter circular loop. Both loops lie in the same plane. The current in the outer loop changes from +1.0 A to -1.0 A in 0.10 s. What is the induced current in the inner loop?

2. Relevant equations
$$\epsilon = \frac{\delta \Phi}{\delta t}$$

3. The attempt at a solution

I'm not sure how to relate $$\frac{\delta I}{\delta t}$$ to Lenz's Law. Just a hint would be great.

Last edited: Apr 25, 2008
2. Apr 26, 2008

### G01

For there to be an induced emf in the inner loop, there must be a changing magnetic flux through the loop. What is causing this magnetic flux?