LAB ACTIVITY CLASS X Dispersion of Light

DISPERSION OF LIGHT

Aim: To know the dispersion of light in

triangular film.

Apparatus: Prism, torch, cardboard sheet, paper sheet.

Procedure:

1. Place a triangular prism on a table.

2. Make a narrow slit in the middle of a card

board. Allow light rays fall on the card board

sheet to produce a thin beam of light.

3. Place a pris in the path of this thin beam of

light so that the light falls at an acute angle

on one of the faces of the prism.

4. Place a sheet of paper facing the opposite

face of the prism.

5. Turn the prism slowly until a band of

colours appears on the sheet of paper.

Observations:

1. When white light passes through a prism, it splits into seven colours.

2. The colours are Violet, Indigo, Blue, Green,Yellow, Orange and Red.

3. The red colour has low deviation and violet colour has more deviation.

Result analysis:

1. The spitting of white light into its

component colours is called dispersion.

2. The band of coloured components is called

its spectrum.

3. Dispersion results due to the different

extents to which each component colour is

refracted by the medium through which

light passes.

Precautions:

Take care that the light ray and face of the 

prism and screen in straight line. Turn the 

prism slowly until the spectrum appears on 

the screen.