Question

In Young's double-slit interference exoeriment, if the slit separation is made threefold, the fringe width becomes

• A. 6 fold
• B. 3 fold
• C. $3/6$-fold
• D. $1/3$-fold

Answer 1

The correct option is D $1/3$-fold

fringe width $\alpha$ $\frac{1}{d}$
as $d_1=3d$
fringe width becomes $\frac{1}{3}$fold
option $D$ is correct