define reflection and refraction of light
Answers
Answer:
Reflection involves a change in direction of waves when they bounce off a barrier. Refraction of waves involves a change in the direction of waves as they pass from one medium to another. Refraction, or the bending of the path of the waves, is accompanied by a change in speed and wavelength of the waves.
Answer:
Reflection is where light bounces off a surface. What you see in a mirror is a reflection. Light that hits a shiny surface bounces off it with the angle of reflection the same as the angle of incidence. For example, If you hold a mirror at arms length and turn the mirror at 45 degrees, someone away from you but at 45 degrees relative to the mirror will see your reflection.
The angle of incidence is the angle from perpendicular to the surface to the ray of light hitting surface. Similarly, the angle of reflection of the angle from the perpendicular to the surface to the ray of light reflection from the surface.
Refraction is different. Light shining on a surface that lets at least some light pass trough it (i.e. has transparency) will reflect some light and allow some light to pass through it. Now the speed of the rays light that passes through that medium (e.g. Water) travels at a different speed than the speed of the rays of light that travel through the original medium. If the light is coming at a non-perpendicular angle to the surface, the difference in speed cause the rays of light to bend depending on the difference in the speed of light through the two mediums. So if you are above the water, a person under the surface of the water will see you at a different angle than you actually are to them.
Consider, light rays hitting the surface of water at say 45 degrees. There light will reflect off at 45 degrees in the other direction. Some of the light will pass into the water. Now because light travels more slowly through the water, the rays of light will bend away from the surface after it enters the water. (For light coming out of water into air, the light will bend towards the surface after it exits water and enters air).
Now an interesting thing is, the greater the angle of incidence, more light is reflected and less light refracted. At a certain angle, all the light is reflected and no light enters the second medium to be refracted. This means you will get total reflection of the light and no refraction of the light.