Types of wave

Waves may be mechanical (i.e. they require a medium such as air or
water to propagate) or electromagnetic (which propagate in a vacuum)
Waves can be classified as:
a) Transverse – here the disturbance is at right angles to the direction
of the wave. Examples include water waves and light (electromagnetic).

b) Longitudinal – here the disturbance is in the same direction,
parallel to the direction of the waves. Examples include sound and
seismic P waves.

*Particles of the wave vibrates in the same direction as the wave.

Both longitudinal and transverse waves can be represented graphically
as shown below.

Wave pulses and continuous waves
A wave pulse involves a short or single disturbance of the medium it
is travelling in. For example, dropping an object in water may
produce a wave pulse.
Continuous waves involve repeated disturbances of the medium. For
example, to produce continuous waves in a ripple tank, the dipper
would have to be dipped into the tank at regular intervals.

To see where this formula comes from, consider how far the wave
moves in one second.
We know (from the definition of frequency) that there are f waves
each second.
Each wave is of length.
So the total distance moved in one second
But velocity = distance time.

 

Wave properties:
All waves will undergo the following processes according to the same
laws:
reflection
refraction
interference
diffraction
Reflection and its laws
There are two laws of reflection. They apply to both plane (flat) and
curved mirrors (or other reflecting surface for waves other than light).

 

Refractive index
Consider a wave passing from material 1 to material 2. In material 1 its
angle to the normal is 1 and in material 2 it is 2.