Question

For plane electromagnetic waves propagating in the positive Z-direction, the combination which gives the correct possible direction for \( E \) and \( B \) fields respectively is:

• A. \( (-2i - 3j) \) and \( (3i - 2j) \)
• B. \( (3i + 4j) \) and \( (4i - 3j) \)
• C. \( (i - 2j) \) and \( (-2i - j) \)
• D. \( (-2i + 3j) \) and \( (i + 2j) \)

Hint:

The electric field, magnetic field, and wave propagation direction in an EM wave follow the right-hand rule.

Answer 1

The Correct Option is A

Step 1: Understanding the EM Wave Propagation For an electromagnetic wave propagating in the positive Z-direction: The electric field \( E \) is perpendicular to the direction of propagation. 
The magnetic field \( B \) is also perpendicular to the propagation. 
\( E, B, \) and the direction of propagation (Z) should form a right-handed coordinate system. 
Step 2: Check the Cross Product Rule \[ E \times B \propto k \] Verifying for the given vectors: \[ (-2i - 3j) \times (3i - 2j)\] yields a component in the \( k \)-direction, confirming the correct orientation.