Question

The phase difference between electric field \( \vec{E} \) and magnetic field \( \vec{B} \) in an electromagnetic wave propagating along the z-axis is:

• A. Zero
• B. \( \pi \)
• C. \( \frac{\pi}{2} \)
• D. \( \frac{\pi}{4} \)

Hint:

In an electromagnetic wave, the electric and magnetic fields are in phase, meaning they reach their peaks and troughs at the same time.

Answer 1

The Correct Option is A

Electromagnetic Wave Propagation:
- In an electromagnetic wave, the electric field \( \vec{E} \) and the magnetic field \( \vec{B} \) oscillate perpendicular to each other and to the direction of wave propagation.
- The wave equation for the electric and magnetic fields can be written as: \[ E = E_0 \cos(kz - \omega t) \] \[ B = B_0 \cos(kz - \omega t) \] - Both fields oscillate in phase, meaning they reach their maximum and minimum values simultaneously.
- Since their equations contain the same phase term \( (kz - \omega t) \), the phase difference between \( \vec{E} \) and \( \vec{B} \) is zero.
Thus, the correct answer is Zero.