Question

The electric and magnetic field of an electromagnetic wave are

• A. in opposite phase and perpendicular to each other
• B. in opposite phase and parallel to each other
• C. in phase and perpendicular to each other
• D. in phase and parallel to each other.

Answer 1

The Correct Option is C

The question asks about the relationship between the electric and magnetic fields in an electromagnetic wave. To answer this question, let's go through the fundamental characteristics of electromagnetic waves.

1. Nature of Electromagnetic Waves: Electromagnetic waves are transverse waves that consist of oscillating electric and magnetic fields at right angles to each other and the direction of wave propagation.
2. Phase Relationship: In an ideal electromagnetic wave, the electric and magnetic fields are in the same phase. This means they reach their maximum and minimum values simultaneously.
3. Perpendicular Orientation:
   • The electric field (E) and magnetic field (B) are perpendicular to each other. This is consistent with the transverse nature of these waves where both fields lie in the plane perpendicular to the direction of wave propagation.
   • They are always perpendicular to the direction of wave propagation, reflecting Maxwell's equations governing electromagnetic phenomena.

Considering these characteristics, the correct answer is: in phase and perpendicular to each other. This means the electric and magnetic fields oscillate together, are aligned perpendicularly, and travel through the medium.

Let's analyze the options:

• In opposite phase and perpendicular to each other: Incorrect, as the fields are in phase.
• In opposite phase and parallel to each other: Incorrect, as the fields are neither out of phase nor parallel according to electromagnetic theory.
• In phase and perpendicular to each other: Correct, as explained.
• In phase and parallel to each other: Incorrect, since the fields are perpendicular, not parallel.

Thus, based on the characteristics of electromagnetic waves, the electric and magnetic fields are indeed in phase and perpendicular to each other.