Question

In Young's double-slit experiment the spacing between the slits is 'd and wavelength of light used is $6000\mathring{A}$. If the angular width of a fringe formed on a distant screen is $1^0$, then value ${}^{\prime }{d}^{\prime }$ is :

• A. $1mm$
• B. $0.05mm$
• C. $0.03mm$
• D. $0.01mm$

Answer 1

Answer: (C)

$0.03mm$

The angular width of a fringe

${\beta }_{\theta }=\frac{\lambda }{d}=\frac{6000\times {10}^{-10}}{d}$

$\therefore d=\frac{6000\times {10}^{-10}}{\frac{1\times \pi }{180}}=0.344\times {10}^{-4}m$

$=0.03mm$