Waves According to their Amplitude and Phase

Waves According to their Amplitude and Phase
A traveling wave is a wave whose amplitude and phase are the same at each point the wave passes.
Stationary waves are waves whose amplitudes and phases change (not the same) at each point the wave travels.
Wave According to its intermediary medium:
Mechanical waves are waves which in their propagation require intermediary media. Almost all waves are mechanical waves.
Electromagnetic waves are waves which do not require intermediate propagation medium. Example: gamma rays (γ), X rays, ultra violet rays, visible light, infrared, radar waves, TV waves, radio waves.

Stationary Waves (silent)
This stationary wave can occur due to interference (the merging of two waves, namely the incoming and reflected waves). Reflected waves that occur can be in the form of reflections with a fixed tip and can also be reflected reflections are a continuation of the incoming wave (fixed phase), but if the reflection occurs at a fixed end, the reflected wave undergoes a phase reversal (different 1800 phases) to the incoming wave.

Wave Properties
In this discussion we will study the properties of waves which include reflection, refraction, disperse, interference, diffraction, and polarization.

Wave Reflection (Wave Reflection)
Wave Reflection
The reflection of waves in the ripple tank, in this reflection obtained a circle wave whose center is the source of the S wave. The reflected waves generated by the straight plane are also in the form of a circle S as the center of the circle. The distance S to the reflecting plane is the same as the distance s to the reflected plane.
According to Snellius's Law, dating waves, reflected waves, and normal lines are in one plane and the dating angle will be the same as the reflected angle, as shown in the following figure:
For two or three dimensional waves such as water waves, we are familiar with the terms light waves and wavefronts.

Wave face
Front wave (Front wave) is defined as a place where the dots have the same phase in the wave, in the picture next to this circle shows the circle is the wave face. The distance between adjacent wavefronts is equal to one wave (λ). A ray is a line drawn in a direction perpendicular to the wavefront.

Front wave
If the circular waves propagate continuously in all directions then at great distances from the source of the wave, we will see the wave face that is almost straight, as well as waves of sea water until the beach. Such wavefronts are called plane waves.

Sound Waves
In the previous chapter we learned about wave equations
as presented in equation (2.9) and equation (2.19). In this section we will specifically study the problem of sound waves. The study will begin with a description of the application of Hooke's law and Newton's law in the case of propagation of longitudinal waves in the trunk, only then will the same principle be used to discuss sound wave propagation in the fluid where in this case we will use the gas medium as a study material. 3.1. Sound Propagation in Bars The reason why we first examine the propagation of longitudinal waves in rods before discussing the same thing in the gas medium is because the principles of elasticity are much easier to understand, as well as with relatively simplified mathematical descriptions.
Suppose we have a bar with a cross-body A and density ρ as shown in Figure (3.1). In this case we assume that the rod is given a stress disturbance at one end, so that the particles in it experience a deviation from the equilibrium position and then wave propagation occurs along the rod in the direction parallel to the direction of the constituent particles of the rod. .
We can view Figure (3.1) as a state where a force ………… works at a cross-section and points normally along the stem. Then according to Hooke's law,