An elastic circular loop in the plane of the paper lies in a 0.71 T magnetic field pointing into the paper. If the loop's diameter changes from 19.3 cm to 7.2 cm in 0.54 s,
a. what is the magnitude of the average induced emf?
HELP: Use Faraday's Law and evaluate the rate of change of magnetic flux through the loop.
b. If the loop's resistance is 2.6 Ω, what is the average induced current I during the 0.54 s?
[tex]\Delta[/tex][tex]\Phi[/tex]=magnetic flux = BAcos[tex]\theta[/tex]
The Attempt at a Solution
So I used the above equation to find the emf
[tex]\pi[/tex](.0605)2(.71)/.54 = .0151
Where the value for r is the amount that the radius changes in the time given.
This is wrong, and I'm not quite sure what else to try...