Question:
In an electromagnetic wave the electric field vector and magnetic field vector are given as \(\vec{E} = E_0\hat{i}\) and \(\vec{B} = B_0\hat{k}\) respectively. The direction of propagation of electromagnetic wave is along :
In an electromagnetic wave the electric field vector and magnetic field vector are given as \(\vec{E} = E_0\hat{i}\) and \(\vec{B} = B_0\hat{k}\) respectively. The direction of propagation of electromagnetic wave is along :
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The wave travels along the direction of \(\vec{E}\times\vec{B}\) (Poynting vector); compute \(\hat{i}\times\hat{k}\).
Updated On: Nov 4, 2026
- \(\left(\hat{k}\right)\)
- \(\hat{j}\)
- \(\left(-\hat{k}\right)\)
- \(\left(-\hat{j}\right)\)
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The Correct Option is D
Solution and Explanation
In an electromagnetic wave, \(\vec{E}\), \(\vec{B}\) and the direction of propagation \(\hat{n}\) are mutually perpendicular and \(\hat{n} = \hat{E}\times\hat{B}\).
Here \(\hat{E} = \hat{i}\) and \(\hat{B} = \hat{k}\).
\(\hat{i}\times\hat{k} = -\hat{j}\) (since \(\hat{k}\times\hat{i} = \hat{j}\)).
So the wave propagates along \(-\hat{j}\).
Answer: (4) \(\left(-\hat{j}\right)\)
Here \(\hat{E} = \hat{i}\) and \(\hat{B} = \hat{k}\).
\(\hat{i}\times\hat{k} = -\hat{j}\) (since \(\hat{k}\times\hat{i} = \hat{j}\)).
So the wave propagates along \(-\hat{j}\).
Answer: (4) \(\left(-\hat{j}\right)\)
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