Energy and interference of waves

1. Wave energy

1. Wave energy

Be careful ：

In the process of vibration, kinetic energy and potential energy do the same cosine function change with time .
At the maximum displacement , Kinetic energy and potential energy are both 0
In the balance position , Both kinetic energy and potential energy are maximum

1.2 Several terms of wave energy

2. Interference of waves

1. Diffraction phenomenon

When obstacles are encountered during wave propagation , A phenomenon that can bypass the edge surface of an obstacle
The conditions under which diffraction occurs ： Diffractor （ Obstacles or seams ） The linearity of d Not much different from the wavelength , This is why sound tends to diffract

2. Huygens principle

Points of wave propagation in the medium , Can be regarded as the wave source that emits wavelet （ Point wave source ）
All wavelet sources send out many wavelets
The envelope formed by each sub wave , That is, the original wave surface propagates to the new wave surface in a certain time

3. The principle of independence of wave propagation

When several waves meet in a certain region of the medium , Each train of waves will retain all their original characteristics （ frequency , wavelength 、 Direction of vibration ）, And continue to move forward according to their original propagation direction .

4. The superposition principle of waves

When several waves meet at some point in the medium , The vibration of the particle is the synthesis of the vibration when each train of waves exists alone

5. Interference of waves

When waves are superimposed, there is a stable distribution of vibration in space, which is called wave interference
Interference condition ： Same frequency 、 The direction of vibration is the same 、 The phase difference is constant