Find B-Field from E-Field: Correct Answer Revealed

[radiator]

Homework Statement

E = 20 cos(\omegat-50x) \widehat{y} find H in free space?

Homework Equations

I used (\nabla X E ) = -dB/dt , and then integrated that expression with respect to t , for some reason I am getting an incorrect answer ?!

The Attempt at a Solution

the correct answer is H = 0.4 w*(eps) *cos(\omegat-50x) \widehat{z}

 

[Pythagorean]

I used (\nabla X E ) = -dB/dt , and then integrated that expression with respect to t , for some reason I am getting an incorrect answer ?!

The Attempt at a Solution

the correct answer is H = 0.4 w*(eps) *cos(\omegat-50x) \widehat{z}

remember that H and B are not the same.

D = eps*E
and
H = B/mu

also:

( \nabla X H ) = -dD/dt

or for linear media:( \nabla X B ) = mu*eps*dE/dt
also remember that the curl pertains to spatial, not temporal derivatives.