- #1

Angie K.

- 108

- 1

## Homework Statement

An elastic circular loop in the plane of the paper lies in a 0.81 T magnetic field pointing into the paper. If the loop's diameter changes from 19 cm to 6.8 cm in 0.45 s,

a. what is the magnitude of the average induced emf?

b. If the loop's resistance is 2.3 Ω, what is the average induced current

*I*during the 0.45 s?

## Homework Equations

emf = change in flux * B / change in time

magnetic flux = B*A cos Theta

## The Attempt at a Solution

Using the equation from above,

the distance that I am going to use is .19m - .068m = .122 m (change in distance)

magnetic flux = (0.81T)(pi)(0.122m)^2 cos 0

= 3.7875*10^-2 T/m^2

emf = (3.7875*10^-2 T/m^2) / 0.45s = 8.4167*10^-2 Volts

Which is wrong but I am not sure where I went wrong.

Maybe something with the distance? Because I feel like that's the one place where I could have messed up...

Thanks in advance!