# Rotating Square Loop in Constant B-field

1. Apr 21, 2012

### alexcoco

[SOLVED] Rotating Square Loop in Constant B-field

1. The problem statement, all variables and given/known data
2. Relevant equations

$\epsilon$ = - $\frac{d\Phi}{dt}$

$\Phi$ = BAcos($\theta$) = BAcos($\omega$t)

$d\Phi$ = -BA$\omega$sin($\omega$t)

3. The attempt at a solution

I'm trying to study for an exam and I've got this practice question that I can answer but my answer never matches. I keep getting b as an answer and I'm not sure if it's right.

$\epsilon$ = BAcos($\omega$t) = (2T)(0.2m)2(10)sin(10t)

I use t = 2s since it asks for $\theta$ = 20° and I get

$\epsilon$ = (2T)(0.2m)2(10)sin(20) ≈ 0.27 V

Am I making a mistake or a wrong assumption anywhere or could it be the answer is incorrectly marked?

Thanks!

Last edited: Apr 21, 2012
2. Apr 21, 2012

### Steely Dan

Using "10" might be fine inside the argument of the sine function, but if you're taking it outside when you take the derivative, you need to convert it to rad/s.

3. Apr 21, 2012

### alexcoco

Thanks, didn't think of that.