Incorrect statement on wave diffraction

Steps:

• Define wave types: Light waves are transverse electromagnetic waves; sound waves are longitudinal mechanical waves.
• Evaluate Doppler effect: Both waves exhibit frequency shifts due to relative motion, per the Doppler principle.
• Assess diffraction: Both light and sound bend around obstacles, a universal wave phenomenon.
• Check propagation: Light travels through vacuum as electromagnetic radiation; sound requires a medium for particle vibration.

Why C is correct:

• Diffraction occurs in all waves, including longitudinal sound waves, which spread out through barriers as described by Huygens' principle.

Why the others are wrong:

• A: Light's electric/magnetic fields oscillate perpendicular to propagation (transverse); sound's particle motion is parallel (longitudinal).
• B: Doppler effect applies to both, shifting observed frequency based on source-observer velocity.
• D: Sound needs a medium for compression/rarefaction; light propagates as self-sustaining fields in vacuum.

Final answer: C