question_answer

What happens to the fringe pattern when the Youngs double slit experiment is performed in water instead of air?

A)  Shrinks                               

B)  Disappear

C)  Unchanged       

D)  Enlarged

Correct Answer: A

Solution :

In Youngs double slit experiment, let screen is placed at a distance\[D\], \[d\] is the distance between coherent sources. The fringe width is given by                 \[W=\frac{D\lambda }{d}\] where, \[\lambda \] is wavelength of light used. When dipped in water, wavelength is\[{{\lambda }_{\omega }}=\frac{{{\lambda }_{a}}}{\mu },\]hence, it decreases. Therefore, fringe width decreases and hence, fringe pattern shrinks.