For plane electromagnetic waves propagating in the z-direction, which one of the following combinations gives the correct possible direction for E → and B → field respectively?

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TestHub · Accepted Answer

The direction of propagation of electromagnetic wave is along $\vec{E} \times \vec{B}$

Also $\vec{E} \cdot \vec{B} = 0$

When $\vec{E}$ is along $- 2 \hat{i} - 3 \hat{j}$

And $\vec{B}$ is along $3 \hat{i} - 2 \hat{j}$

Then $\vec{E} \times \vec{B} = (- 2 \hat{i} - 3 \hat{j}) \times (3 \hat{i} - 2 \hat{j})$

$= 4 \hat{k} + 9 \hat{k}$

$= 13 \hat{k}$ is along +ve direction also $\vec{E} \cdot \vec{B} = 0$

Physics - EM Waves Question with Solution | TestHub

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