Question

In Young's double slits experiment, the position of $5^{\text {th }}$ bright fringe from the central maximum is $5 \,cm$. The distance between slits and screen is $1 \,m$ and wavelength of used monochromatic light is $600 \,mm$. The separation between the slits is:

• A. $12\, \mu m$
• B. $60\, \mu m$
• C. $36\, \mu m$
• D. $48 \,\mu m$

Answer 1

Answer: (B)

Given
$ D =1 m $
$\lambda=600 \times 10^{-9} m $
$n =5 $
As $ y _{ nth }=\frac{ n \lambda D }{ d } $
$\Rightarrow \frac{5 \times 600 \times 10^{-9} \times 1}{ d }=5 \times 10^{-2} $
$\Rightarrow d =\frac{5 \times 600 \times 10^{-9} \times 1}{5 \times 10^{-2}}=60 \times 10^{-6} m$
$\Rightarrow d =60\, \mu m$