Answer:
A wave is a disturbance of the space (or of a medium), that carries energy without transmitting matter.
A wave is produced when there is a periodic vibration in the particles of a medium (mechanical wave), or when there is a periodic oscillation of the electric and magnetic fields (electromagnetic waves). Electromagnetic waves are the only ones that can travel through a vacuum.
Mechanical waves are further classified into two types, depending on how the particles in the medium vibrate:
- If they vibrate up and down (perpendicular to the direction of motion of the wave), they are called transverse waves
- If they vibrate back and forth (parallel to the direction of motion of the wave), they are called longitudinal waves
In general, waves are generated from a precise point in the space, which is called source of the wave. The source of the wave does work, since it is responsible for starting the motion of the particle, and make them starting vibrating, so it transmits energy to the particles.
