question_answer

In Youngs double slit experiment, the separation between the slits is made 3 fold, the fringe width becomes

A)  \[\frac{1}{3}Times\]                      

B)  \[\frac{1}{9}Times\]

C)  \[3\,Times\]                     

D)  \[9\,Times\]

Correct Answer: A

Solution :

                 The fringe width \[(\beta )\] is given by                 \[\beta =\frac{D\lambda }{d}\]                  When separation of slits is d = 3 d then \[\beta =\frac{D\lambda }{3d}=\frac{\beta }{3}\]