Question

The direction of propagation of electromagnetic wave is along

• A. Electric field vector, $\vec{E}$
• B. Magnetic field vector, $\vec{B}$
• C. $\vec{E} \cdot \vec{B}$
• D. $\vec{E} \times \vec{B}$
• E. $\vec{B} \times \vec{E}$

Hint:

Right-hand rule: $\vec{E} \times \vec{B}$ gives direction of propagation.

Answer 1

The Correct Option is D

Concept:
Direction of EM wave propagation: \[ \vec{S} = \vec{E} \times \vec{B} \]

Step 1: Understand vectors.
\[ \vec{E} \perp \vec{B} \]

Step 2: Direction.
Wave travels in direction perpendicular to both $\vec{E}$ and $\vec{B}$. \[ \text{Direction} = \vec{E} \times \vec{B} \]