In a Young's double slit experiment, the source is white light. One of the holes is covered by a red filter and another by a blue filter. In this case

Options

A. there shall be alternate interference patterns of red and blue.
B. there shall be an interference pattern for red distinct from that for blue.
C. there shall be no interference fringes.
D. there shall be an interference pattern for red mixing with one for blue.

Answer

C

Explanation

there shall be no interference fringes.
In Young.s original double slit experiment, monochromatic light with definite frequency was used. Hence the two slits behave like coherent sources and they can produce stationary interference pattern on the screen.
But here light waves emitted by two slits have different frequencies and hence different colours. Hence phase difference between them does not remain constant and so they behave like non-coherent sources. Hence they can not produce any stationary interference on the screen and so we do not obtain interference fringes.