Question

If the source of light used in a Young's double slit experiment is changed from red to violet :

• A. consecutive fringe lines will come closer
• B. the central bright fringe will become a dark fringe
• C. the fringes will become brighter
• D. the intensity of minima will increase

Answer 1

Answer: (A)

$\beta=\frac{\lambda \cdot D}{d}$
$\lambda_{R} >\lambda_{V}$
$\beta_{R}=\frac{\lambda_{R} D}{d}$
and $\beta_{v}=\frac{\lambda_{V} D}{d}$
$\beta_{R} >\beta_{v}$
Fringe pattern will shrink.