What are all of the wave laws?
The law of reflection is angle of incidence=angle of reflection; and the law of refraction is Snell's Law [sinangle1=sinangle2].
Are there any other major laws [ex. For diffraction, doppler effect].
Thank you.

Wave laws?

If you want some formulae, the ones I know are:

v = f\lambda

In double slit experiment:

\frac{d}{l} = \frac{x}{\lambda}

In diffraction grating:

d\ sin\theta = n\lambda

To add "matter waves" to the list :) [De Broglie Relation]
wavelength = Planck's constant / Momentum

The equation for the observed frequency of sound when the source is traveling toward you is:

for = fv/(v − vt)

where

for is the observed frequency
f is the emitted frequency
v is the velocity of sound
vt is the velocity of the source toward you
v > vt (vt is less than v)
Note that this equation does not work if the speed of the source is equal to the speed of sound. In such as case, you would be dividing by 0, which is impossible.

Wavelength

Also, since the velocity of the wave equals the frequency times the wavelength (v = fλ or f = v/λ), the equation for the observed wavelength when the source is traveling toward you is:

λo = λ(1 − vt/v)

where

λo is the observed wavelength
λ is the emitted wavelength (Greek symbol lambda)
v > vt (vt less than but not equal to v)
Velocity

If you know the resulting frequency, you can find the speed of the source moving toward you:

vt = v(f/fo + 1)

When the source of sound is moving away from you, the pitch you hear is lower, the frequency is slower and the wavelength is longer than what was emitted from the source.

Note that the equations are the same as when the source is moving toward you, except that the "−" sign is replaced by a "+" sign to indicate the change in direction of the source. In the case of velocity, the "+" sign is replaced by a "−" sign.

The equation for the observed frequency of a waveform when the source is traveling away from you is:

for = fv/(v + va)

where va is the velocity of the source away from you.

The equation for the observed wavelength when the source is traveling away from you is:

λo = λ(1 + va/v)

The equation for the velocity of the source, when it is traveling away from you is:

va = v(f/fo − 1)