Step 1: Understanding the Concept:
Waves can be broadly classified based on the direction of vibration of the medium's particles or the oscillation of fields relative to the direction of propagation.
1. Longitudinal Waves: In these waves, the particles of the medium vibrate back and forth along the same direction as the wave's travel. A classic example is sound waves in air.
2. Transverse Waves: In these waves, the vibrations or oscillations occur in a direction perpendicular (at right angles) to the direction of energy transfer. Examples include waves on a string or ripples on water.
3. Mechanical vs Non-mechanical: Mechanical waves require a physical medium (like air, water, or a solid) to travel. Electromagnetic waves are non-mechanical because they can propagate through a vacuum.
Step 2: Detailed Explanation:
Electromagnetic (EM) waves consist of oscillating electric and magnetic fields.
Theoretical derivations from Maxwell's equations and experimental observations (such as polarization) prove that these fields vibrate perpendicularly to each other.
More importantly, both the electric field vector (\(\vec{E}\)) and the magnetic field vector (\(\vec{B}\)) oscillate in a plane that is perpendicular to the direction in which the wave is traveling.
If a wave is moving along the positive x-axis, the electric field might oscillate along the y-axis, and the magnetic field would then oscillate along the z-axis.
Since the "vibrations" (field oscillations) are at \(90^{\circ}\) to the path of the wave, EM waves are strictly "transverse" in nature.
The most conclusive evidence for the transverse nature of light is the phenomenon of polarization.
Only transverse waves can be polarized (restricted to a single plane of vibration).
Longitudinal waves like sound cannot be polarized because their vibration is always aligned with the axis of propagation.
Since light can be polarized by a polaroid sheet, it must be transverse.
Step 3: Final Answer:
Electromagnetic waves are transverse waves because their oscillations are perpendicular to the direction of propagation.
Therefore, the correct option is (C).