Question

The change in the diffraction pattern of a single slit, when the monochromatic source of light is replaced by a source of white light will be

• A. Diffracted image is not clear
• B. Diffracted image gets dispersed into constituent colours of white light
• C. The image of the slit becomes infinitely wide
• D. Clear colourful fringe pattern

Answer 1

The correct option is B

Diffracted image gets dispersed into constituent colours of white light

Explanation for the correct option:

Option B:

1. When a monochromatic source is replaced by a white light, the diffracted image of the slit will get dispersed into constituent colors of white light.
2. The central maxima will be white, and all other fringes will be of the constituent colors.

Explanation for incorrect options:

Option A

1. The diffracted pattern won't be completely unclear.
2. The first few fringes obtained will be clear and then as the order increases the clearness of the pattern decreases. So, this option is incorrect.

Option C

There is no change in the slit on changing the type of light. So, this option is incorrect.

Option D

1. The central fringe will be white and the other fringes will be colorful. But the pattern will not be completely clear.
2. The first few fringes obtained will be clear and then as the order increases the clearness of the pattern decreases. So, this option is incorrect.

Hence option B is correct.