Prove that emf from E equals emf from dB/dt

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The discussion focuses on proving the equivalence of two electromotive forces (emf), e1 and e2, defined by the integrals e1 = ∫E*dl and e2 = ∫dB/dt*dS. The electric field E is represented as E = E0*sin(kx - wt), while the magnetic field B is assumed to be B = B0*sin(kx - wt). The challenge lies in integrating the time derivative of the magnetic field, dB/dt, over a surface S, particularly when considering the wave's lack of thickness. The participants emphasize the need for clarity in handling the integration and the implications of the wave's properties.

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Addez123
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Exercise:
I'm suppose to prove that e1 = e2
e1 = ∫E*dl
e2 = ∫dB/dt*dS

where S is the surface encircled by the conture c.
c is a box with with a length (in x axis) and b height (in y axis).
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for an electromagnetic wave:
E = E0*sin(kx - wt) (in y axis)

I'm ASSUMING this means that
B = B0*sin(kx - wt) (in z axis)

Pathetic Attempt:
e1 calculated on the outside of c becomes
b*E(x + a,t) - b*E(x,t) =
E0*sin(kx + ka - wt) + E0*sin(kx - wt)
This expression is confusing and doesn't lead to any simplification at all.

e2 = ∫dB/dt*dS
dB/dt = B0*-w*cos(kx - wt)

Now here's the tricky part, how do I integrate this infinitly thing vector over a surface?
The wave has no thickness, shouldn't the integral be zero?!
 
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I'm also suppose to prove this explicitly, I DONT EVEN KNOW WHAT THAT MEANS!
 
Addez123 said:
e1 calculated on the outside of c becomes
b*E(x + a,t) - b*E(x,t) =
E0*sin(kx + ka - wt) + E0*sin(kx - wt)
What happened to the factor of b in going to the last line. Also, what happened to the negative sign between the two terms?

This expression is confusing and doesn't lead to any simplification at all.
You've made a good start once you make the corrections above.

e2 = ∫dB/dt*dS
dB/dt = B0*-w*cos(kx - wt)
OK

Now here's the tricky part, how do I integrate this infinitly thing vector over a surface?
The wave has no thickness, shouldn't the integral be zero?!
Not sure what you mean by "this infinitly thing vector".
##\frac{\partial B}{\partial t}## is a function of ##x## and ##t##. ##t## is some fixed but arbitrary time. So, you can think of ##\frac{\partial B}{\partial t}## as a function of ##x## that you need to integrate over the rectangular area. What would be a good way to break up the area into infinitesimal elements ##dS##? Recall how you did similar integrals in your calculus course.
 

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