# ElectroMagnetic Induction - HELP!

1. Nov 3, 2008

### krugertown

A 20cm x 20cm square loop of wire lies in the xy-plane with its bottom edge on the x-axis. The resistance of the loop is 0.50$$\Omega$$. A uniform magnetic field parallell to the z-axis is given by B=0.80y$$^{2}$$t, where B is in tesla, y in meters, and t in seconds. What is the size of the induced current in the loop at t = 0.50s?

Induciton of Solonoid = ((magnetic constant)N^2A)/I
$$\epsilon$$ = d$$\phi$$/dt
$$\phi$$ = magnetic flux

i thought first i would need to differentiate the original equation to find the emf of the loop and hence the current.
but thats where i got stuck? where does the y value come in?

once ive got the current i can find the induced current but am struggling with how to get the emf of the loop!

help would be appreciated!

2. Nov 3, 2008

### marcusl

The B field is non-uniform and it's value depends on y. You will have to integrate it to find the enclosed flux. Your second equation gives the emf (although you left off the negative sign). That and the resistance give the current.

Last edited: Nov 3, 2008