### Neet Solved Paper 2015 Question 38

##### Question: In a double slit experiment, the two slits are 1 mm apart and the screen is placed 1 m away. A monochromatic light of wavelength 500 nm is used. What will be the width of each slit for obtaining ten maxima of double slit within the central maxima of single slit pattern.

#### Options:

A) 0.2 mm

B) 0.1 mm

C) 0.5 mm

D) 0.02 mm

## Show Answer

#### Answer:

Correct Answer: A

#### Solution:

Given $ d=1,mm=1\times {10^{-3}}m $ $ D=1m $ $ \lambda =500nm=5\times {10^{-7}}m $

As width of central maxima = width of 10 maxima

$ \therefore $ $ \frac{2D\lambda }{a},=10,( \frac{\lambda D}{d} ) $

$ \Rightarrow $ $ a=\frac{d}{5},=\frac{{10^{-3}}}{5},=0.2,\times {10^{-3}},m $ $ a=0.2,mm $