Question

In a biprism experiment, the wavelength of monochromatic light is $6000\mathring{A}$. The distance between the two virtual images is $6mm$. Number of fringes formed per mm on a screen at a distance of $1m$ is

• A. $5$
• B. $10$
• C. $15$
• D. $20$

Answer 1

The correct option is B $10$

$\beta =\frac{\lambda D}{d}$
$\beta =\frac{6\times {10}^{-7}\times 1}{6\times {10}^{-3}}={10}^{-4}m$
Number of fringes$=\frac{1\times {10}^{-3}}{{10}^{-4}}=10$