What is a mechanical wave?

A mechanical wave is defined as a wave that requires a medium to travel through, which directly aligns with the definition provided in the correct answer. These waves need a substance—such as solid, liquid, or gas—to propagate, meaning they cannot exist in a vacuum where no particles are present to facilitate wave movement.

Examples of mechanical waves include sound waves, which travel through air, and water waves, which move across the surface of a body of water. The presence of a medium is essential for the transmission of energy in mechanical waves, as the medium’s particles oscillate and transfer energy from one particle to another.

In contrast, waves that can travel through a vacuum, like electromagnetic waves (e.g., light waves), do not belong to the category of mechanical waves since they do not require a medium for propagation.