Question

In Young's double slit experiment, interference pattern will not be seen if one uses

• A. a LASER as the source of light
• B. two LASER sources in front of two slits
• C. two sodium light lamps in front of two slits
• D. in both (b) and (c) above

Answer 1

Answer: (D)

in both (b) and (c) above

A single source of light would be divided into to sources of light by division of amplitude or division of wave front to produce coherent sources of light.

But when two physically different sources are used, they cannot be made coherent practically. Thus they do not give interference pattern.