What is the source of energy for waves?

Answer 1

The question asks for the source and may mean the energy source that generates the waves. Alternatively, the question may be asking how waves can be a source of energy. In the first case, energy goes into the wave and in the second case energy comes out of the wave.

Briefly, waves are the regular repetition of an action, which may be vertical rise and fall of water as in water waves or compression and rarefaction of air as in sound waves or regular variations in electromagnetic fields as in light or radio waves. In all these cases, waves also move which is another characteristic. (To get technical, there are also standing waves but such waves may be taken to be two counter moving waves.)

Physical waves are generated when the medium in which they exist is caused to move by some source of energy. A vibrating drum head makes a sound wave. The wind makes water waves. In the case of electromagnetic waves, the source of the fields, i.e. charges and currents, move in a regular way to generate the waves. The "source" of energy is the the energy that goes into moving the medium, e.g. the wind or mechanical motion of the drum membrane or the causative forces that move charges and currents in electromagnetic waves. In these cases, energy comes from the "source" to create the wave.

To have a wave act as an energy "source", or to get energy out of a wave, you have to have the waving or oscillating material exerting a force on something else. Clearly, water waves may exert a buoyant force on a floating object, for instance, and that floating object as it moves up and down may exert a force and thereby do work and so act as an energy source. The same applies to sound, but the pressure waves are typically going to create movement over very small, perhaps micron scales, so mechanical work is less obvious. Perhaps more obvious would be sound causing an object to vibrate and that vibration being converted into heat energy. In the case of electromagnetic waves, the microwave oven actually heats objects by having the electromagnetic waves act on charges in atoms and molecules which then physically move and vibrate and that motion is heat.

In summary, there are many kinds of waves and to create a wave there must be an energy source. The waves then contain that energy and the energy can be extracted from the wave thereby diminishing the wave.

Answer 2

Disturbance is the source of Energy .i.e. Waves :D

Answer 3

The source of all waves - mechanical or electromagnetic - is something that is vibrating.

Answer 4

• the moon controls the waves and how they act

Answer 5

Vibration.