Refraction and Reflection of Waves
Refraction
Any type of wave can be refracted, which means a change of direction.
Refraction can occur when the speed of a wave changes,
as it moves from one environment to another.
as it moves from one environment to another.
After refraction, the wave has the same frequency but a different speed, wavelength and direction.
When a wave enters a new environment,
its change in speed will also change its wavelength.
its change in speed will also change its wavelength.
If the wave enters the new environment at any angle
other than normal to the boundary,
then the change in the wave's speed will also change its direction.
This is most easily shown with water waves.
other than normal to the boundary,
then the change in the wave's speed will also change its direction.
This is most easily shown with water waves.
Reflection
.
Any type of wave can be reflected.
We shall look at the reflection of Sound, Water and Light Waves.
Reflection best occurs from flat, hard surfaces.
After reflection, a wave has the same speed, frequency and wavelength,
it is only the direction of the wave that has changed.
We shall look at the reflection of Sound, Water and Light Waves.
Reflection best occurs from flat, hard surfaces.
After reflection, a wave has the same speed, frequency and wavelength,
it is only the direction of the wave that has changed.
For light (and other electromagnetic radiation)
a flat shiny surface, like a plane mirror, is a good reflector.
A plane mirror is one which is straight and not curved.
a flat shiny surface, like a plane mirror, is a good reflector.
A plane mirror is one which is straight and not curved.
The light ray which hits the mirror is called the incident ray.
The light ray which bounces off the mirror is called the reflected ray.
The light ray which bounces off the mirror is called the reflected ray.
The angle of incidence equals the angle of reflection, i = r.
This means that whatever angle the light ray hits the mirror,
it will be reflected off at the same angle
(like snooker balls bouncing off a cushion).
If the surface of the mirror is not smooth but rough or bumpy,
then light will be reflected at many different angles.
The image in the mirror will be blurred and unclear.
This is called diffuse reflection.
then light will be reflected at many different angles.
The image in the mirror will be blurred and unclear.
This is called diffuse reflection.
When you look into a mirror,
you see a reflection which is an image of the real object.
you see a reflection which is an image of the real object.
The image appears to be the same distance behind the mirror
as the real object is in front of it.
This is because the brain thinks that light travels in straight lines
without changing direction.
as the real object is in front of it.
This is because the brain thinks that light travels in straight lines
without changing direction.
The image is called virtual because the light rays (shown as dotted lines)
never really go there.
The virtual image is the same size as the object
but with left and right reversed.
never really go there.
The virtual image is the same size as the object
but with left and right reversed.
good luck
mohamed hassaan
