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An electromagnetic wave in vacuum has the electric field E and magnetic field B, which are always perpendicular to each other. The direction of polarization is given by X̂ and that of wave propagation by k̂. Then

1. X̂ ∥ B̂ and k̂ ∥ B̂×Ê
2. X̂ ∥ Ê and k̂ ∥ Ê×B̂
3. X̂ ∥ B̂ and k̂ ∥ Ê×B̂
4. X̂ ∥ Ê and k̂ ∥ B̂×Ê

Correct answer: X̂ ∥ Ê and k̂ ∥ Ê×B̂

Solution

The correct option states that the direction of polarization (X̂) is aligned with the electric field (Ê), which is true since polarization refers to the orientation of the electric field in an electromagnetic wave. Additionally, the wave propagation direction (k̂) is perpendicular to both the electric and magnetic fields, which is represented by the cross product Ê×B̂, confirming the relationship between these vectors in electromagnetic waves.

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