Question

Polarisation of light proves that light waves are:

• A. Longitudinal
• B. Transverse
• C. Stationary
• D. Electromagnetic only in vacuum

Hint:

Keep this clear rule in mind: Common wave behaviors like Interference and Diffraction happen for *both* longitudinal and transverse waves. However, Polarization is a unique property *exclusively* possible for Transverse Waves.

Answer 1

The Correct Option is B

Concept: Wave propagation can be classified based on the orientation of particle or field oscillations relative to the direction of energy travel. Polarization is an optical phenomenon where oscillations are restricted to a single plane perpendicular to the direction of propagation.

Step 1: Differentiate between longitudinal and transverse wave traits.

• Longitudinal Waves: The oscillations occur parallel to the direction of wave travel (e.g., sound waves). Because their vibrations point along the axis of movement, they look symmetrical from all sides and cannot be polarized.
• Transverse Waves: The oscillations occur perpendicular to the direction of wave travel (e.g., strings, light). Since these vibrations happen along a perpendicular plane, they can be restricted to a single line or direction within that plane.

Step 2: Analyze the implication of light polarization.
Interference and diffraction confirm that light behaves as a wave, but they do not reveal its specific directional nature. Because light can be polarized using a polaroid crystal—filtering out all orientations except a single perpendicular plane—it serves as definitive, direct experimental proof that light waves must be Transverse waves.