An electromagnetic wave is propagating in a vacuum with an electric field given by E = E0 sin(kx - omega*t) j-cap. What is the direction of the magnetic field vector B associated with this wave?

A. k — The direction of propagation is given by the cross product of the electric and magnetic field vectors, specifically the direction of the Poynting vector is E cross B. Since the wave propagates in the x-direction and E is in the y-direction, B must be in the z-direction to satisfy the right-hand rule.

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$An electromagnetic wave is propagating in a vacuum with an electric field given by E = E_{0} sin (k x - ω t) \hat{j} . What is the direction of the magnetic field vector B associated with this wave?$

A. $\hat{k}$
B. $- \hat{k}$
C. $\hat{i}$
D. $- \hat{j}$

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Correct answer: A — $\hat{k}$

Solution

The direction of propagation is given by S \propto E \times B . Given E = E_{0} \hat{j} and propagation direction \hat{i}, we have \hat{i} = \hat{j} \times B, which implies B must be in the \hat{k} direction.

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An electromagnetic wave is propagating in a vacuum with an electric field given by E=E0​sin(kx−ωt)j^​. What is the direction of the magnetic field vector B associated with this wave?

Solution

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More Electromagnetic Waves practice questions

$An electromagnetic wave is propagating in a vacuum with an electric field given by E = E_{0} sin (k x - ω t) \hat{j} . What is the direction of the magnetic field vector B associated with this wave?$