Q. In a Young’s double slit experiment, the slit separation is $0.2cm$, the distance between the screen and slit is $1m$. Wavelength of the light used is $5000\ \mathring{\mathrm{A}}$. The distance between two consecutive dark fringes (in $mm$) is
A) 0.25
B) 0.26
C) 0.27
D) 0.28
Explanation
(a) Distance between two consecutive dark fringes
$\beta = \frac{\lambda D}{d} = \frac{5000 \times 10^{- 10} \times 1}{0.2 \times 10^{- 2}} = 0.25\ mm$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.