# Graph of periodic motion due to wave

Wave is a disturbance in a medium, due to this disturbance the particles in the medium oscillate. Due to this oscillation we say that the wave is sinusoidal because the motion of the particle is periodic. So we REPRESENT the motion in sine wave.

Periodic motion can be represented by sine graphs. So if instead of representing in sine graph can we represent it as square (instead of curves) periodic graph ?.

Ps: also please confirm if the first paragraph is correct (kind of confused in that too).

• Only motions of the kind as seen here can be represented by a sine curve. These are called simple harmonic oscillations. Other periodic waves, like square waves and so on can be written as a combination of these sine waves. That is why we study just the sine waves. Feb 7 '20 at 18:51

Re.

Due to this oscillation we say that the wave is sinusoidal because the motion of the particle is periodic

Sinusoidal motion is not required for oscillation. For example square waves or triangular waves oscillate.

So if instead of representing in sine graph can we represent it as square (instead of curves) periodic graph ?.

YES.

• Care to elaborate a bit on your answers? I suggest that a small explanation and maybe an example (like the square wave you provided) could be quite instructive. Feb 7 '20 at 17:56
• Thanks. Btw is the first paragraph of my question correct ?. Also you said "square wave oscillate", is it correct to say that waves vibrate and not the particles ?. Feb 7 '20 at 17:56
• @ZaellixA refer physics.stackexchange.com/questions/517334/… Feb 7 '20 at 18:00
• @user253164 Re 'is it correct to say that waves vibrate and not the particles ?" Either is correct but "waves vibrate is more common". Note that there are no particles in electromagnetic waves. Feb 7 '20 at 18:40
• @ ZaellixA Google 'square wave generator' or 'square wave' Feb 7 '20 at 18:53

If the wave is in a medium consisting of particles, the graph generally represents the actual displacement of the particles from their equilibrium position as a function of position and/or time. If he wave is in a field, the graph represent the deviation in the field strength. The initial wave form is determined by the source but any form can be considered as a combination of sinusoidal waves.