How to Calculate Time Dependent Magnetic Field with Faraday's Law

[annastewert]

Homework Statement

See attached photo. It has question and answers.

Homework Equations

Maybe integral of B.dL=Mo i ? I'm not sure

The Attempt at a Solution

I tried using the above equation and solved for i but it gives i with respect to time and the answer is 10A. I'm not sure how to get an answer without t.

 

[annastewert]

Sorry I forgot the picture

 

[rude man]

Y ou're not thinking of the right law.
Think Maxwell, specifically ∇ x E = -∂B/∂t. Then go to Stokes.

EDIT: Or Faraday: compute the whole dΦ/dt for your area. I guess that is more straight-forward.
(You can do this in your head!)