Refraction of ight

Define optical medium

A medium through which light rays pass through

What is refraction?

When a light ray passes from one optical medium to another medium of a different density, it deviates from its path by a certain angle at the surface of separation of the 2 mediums.

Why does refraction occur?

Because speed of light changes when it moves from one medium to another

Why does speed of light change when it moves from one medium to another?

Due to the change in density of the mediums

Define Incident Ray

The ray that strikes the surface of separation of 2 optical mediums

Define Refracted ray

From the point of incidence, the ray that changes its direction in the next medium

Define Angle of Incidence

The angle an incident ray makes with the normal

Define Angle of Refraction

The angle formed between the refracted ray and the normal

Define Normal

The straight line perpendicular to the surface of the medium and passing through the point of incidence.

Define point of incidence

The point of the surface of separation of the two mediums where the incident ray strikes

When light travels from denser to rarer it-

Bends away from the normal

Whem light travels from rarer to denser it-

bends towards the normal

Define refractive index

Ratio of speed of light in a medium to speed of light in vacuum

Refractive index of vacuum

1

Refractive index of air

1.003

Refractive index of water

1.3

Refractive index of oil/cedar

1.5

Refractive index of diamond

2.4

Refractive index of dense flint glass

1.6

1st law of reflection

The incident ray, refracted ray nd normal to the interface lie in the same plane

2nd law of refraction

The ratio of the sine of the angle of incidence to the sine of the angle of refraction for any 2 mediums is always constant.

The value of this constant is the refractive index of the second medium with repect to that if the first

What is a prism?

A transparent piece of glass or other material with plane surfaces.

Define dispersion of light

The splitting of white light into its component colours

Define visible spectrum

The range on colours obtained by dispersion of white light

Wavelength of violet

400-440 nm

Wavelength of indigo

440-460 nm

Wavelength of blue

460-500 nm

Wavelength of green

500-570 nm

Wavelength of yellow

570-590 nm

Wavelength of orange

590-620 nm

Wavelength of red

620-720 nm