[quote author=Fu-Kwun Hwang link=topic=915.msg5181#msg5181 date=1260583960]
Assume the width and height of the loop are d and h.
The magnetic flux in the loop is \Psi =\int \vec{B}\cdot d\vec{A}= \vec{B}\cdot \vec{A(t)} =B d h \cos\omega t

So the induced emf \epsilon= -\frac {d\Psi}{dt}=B (dh) \omega \sin\omega t=BA_{max} \omega \sin\omega t

should be
is \Psi =\int \vec{B}\cdot d\vec{A}= \vec{B}\cdot \vec{A(t)} =B d h \sin\omega t
I check by sub t=0 ,  $\Psi =0.
The initial condition is causing the error in your equation. Right ?