Pdagogy seminar light

SUBMITTED BY: INDU G

PHYSICAL SCIENCE

REG NO :13383011

SUBMITTED TO: LINI MOL K. S

• How a light ray is deviated by a prism,

• How white light is dispersed by a prism,

• The colours of a white light spectrum,

• About the wavelengths of different

colours.

Here is a

glass prism:

A ray of white light

arrives

It is (mainly) reflected or refracted

? away from or towards

the normal the normal

What happens to the ray of

light?

But different colours are refracted by

different angles.

In fact, the ray is :

• (bent through an angle), and

• dispersed (split up into separate

colours)

like this.

What happens now?

R

Vscreen

Red is deviated most / least ?

Violet is deviated most / least ?

least

most

R

Vscreen

There is a spectrumon the screen:

Red Orange Yellow Green Blue Indigo Violet

ROY G BIV

Perhaps the most spectacular and best known atmospheric optical phenomenon is the rainbow.

Sunlight and water droplets are necessary for the formation of a rainbow.

Furthermore, the observer must be between the Sun and rain.

When a rainbow forms, the water droplets act as prisms and refraction disperses the sunlight into the spectrum of colors, a process called dispersion.

The curved shape of the rainbow results because the rainbow rays always travel toward the observer at an angle between 40 and 42° from the path of the sunlight.

Why is a Rainbow Curved?

The primary colours :

› Red ( R )

› Green ( G )

› Blue ( B )

The primary colours add together to make white.

The secondary colours

› Cyan ( C )

› Magenta ( M )

› Yellow ( Y )