Electromagnetic waves in magnetised media — name the rotation of the plane of linear polarization The rotation of the direction of the E-field of a linearly polarized wave as it passes through a magnetised ferric (ferrite) medium is called:

Introduction / Context:
When a linearly polarized electromagnetic wave propagates through a magnetised ferrite, its plane of polarization can rotate due to non-reciprocal circular birefringence. This phenomenon has important applications in isolators, circulators, and contactless current sensors. The question asks you to identify the correct name for this rotation.

Given Data / Assumptions:

• Medium: magnetised ferric/ferrite material under a bias magnetic field.
• Incident wave: linearly polarized.
• Observation: rotation of polarization plane after transmission.

Concept / Approach:
The effect is called Faraday rotation. Under magnetization, the right- and left-circularly polarized components of the wave experience different propagation constants. Their phase difference accumulates along the path, resulting in a rotation of the net linear polarization. The rotation angle is proportional to the Verdet constant of the material and the line integral of magnetic field along the path.

Step-by-Step Solution:

Verification / Alternative check:
Non-reciprocity (rotation direction independent of propagation reversal) underlies the operation of ferrite isolators and circulators used in microwave systems.

Why Other Options Are Wrong:

• Lorentz, Steinmitz, Fleming: not the standard names for this polarization-rotation phenomenon in magneto-optic/magneto-microwave contexts.

Common Pitfalls:
Confusing Faraday rotation with optical activity in chiral media (which is reciprocal) or with mechanical rotation of components.

Final Answer:
Faraday rotation