Question

In double-slit experiment using light wavelength $600nm$, the angular width of a fringe formed on a distant screen is ${0.1}^o$. What is the spacing between the two slits?

Answer 1

$\beta =\frac{\lambda D}{d}$

$\Rightarrow \left(\frac{\beta }{D}\right)=\frac{\lambda }{d}$

$\Rightarrow \left({0.1}^0\right)=\frac{600\times {10}^{-9}}{d}$

$\Rightarrow \frac{0.1\times \pi }{180}=\frac{600\times {10}^{-9}}{d}$

$d=\frac{600\times 1800\times {10}^{-9}}{\pi }$

$d=\frac{108\times {10}^{-5}}{\pi }M$

$\Rightarrow$ distance between

$slits=\frac{180\times {10}^{-5}}{\pi }M.$