Question

In the figure given below, a narrow beam of white light is shown to pass through a triangular glass prism. After passing through the prism, it produces a spectrum XY on the screen.
(i) Name the phenomenon.
(ii) State the colours seen at X and Y.
(iii)Why do different colours of white light bend at different angles through a prism?

Answer 1

i) DEPRESION OF LIGHT

ii) X-- violet

And

Y-- Red

iii) It is because different colours have different wavelength

Answer 2

i) When a narrow beam of white light is shown to travel through a triangular glass prism, it produces a spectrum on the screen. This phenomenon is called dispersion of light.

ii) X is violet and Y is red.

iii) The Colours of white light bend at different angles through a prism because they have different wavelengths.

• A light ray bends when it travels from one medium through other. This is called refraction.

• Since each color of white light travels at a different speed, they bend at different angles when they travel from one medium to another.
• Each color of white light has different wavelengths.