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B-field from E-field

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1. Homework Statement

E = 20 cos([tex]\omega[/tex]t-50x) [tex]\widehat{y}[/tex] find H in free space?

2. Homework Equations

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

3. The Attempt at a Solution

the correct answer is H = 0.4 w*(eps) *cos([tex]\omega[/tex]t-50x) [tex]\widehat{z}[/tex]
 
Last edited:

Pythagorean

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

3. The Attempt at a Solution

the correct answer is H = 0.4 w*(eps) *cos([tex]\omega[/tex]t-50x) [tex]\widehat{z}[/tex]


remember that H and B are not the same.

D = eps*E
and
H = B/mu

also:

( [tex]\nabla[/tex] X H ) = -dD/dt

or for linear media:


( [tex]\nabla[/tex] X B ) = mu*eps*dE/dt



also remember that the curl pertains to spatial, not temporal derivatives.
 

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