Question

A plane electromagnetic wave propagating along y-direction can have the following pair of electric field (\(\vec{E}\)) and magnetic field (\(\vec{B}\)) components:

• A. \(E_y, B_y\) or \(E_z, B_z\)
• B. \(E_x, B_y\) or \(E_y, B_x\)
• C. \(E_x, B_z\) or \(E_z, B_x\)
• D. \(E_y, B_x\) or \(E_x, B_y\)

Hint:

EM waves are transverse. No component of the field can ever exist in the direction of propagation.

Answer 1

The Correct Option is C

Step 1: In an EM wave, \(\vec{E}\), \(\vec{B}\), and the direction of propagation are all mutually perpendicular.
Step 2: If propagation is along the \(y\)-axis, both \(\vec{E}\) and \(\vec{B}\) must lie in the \(xz\)-plane.
Step 3: This means their components can only be in the \(x\) or \(z\) directions.
Step 4: Thus, the pairs must be (\(E_x, B_z\)) or (\(E_z, B_x\)).