Question

Monochromatic green light of wavelength $5\times {10}^{-7}m$ illuminates a pair of slits 1 mm apart. The separation of bright lines on the interference pattern formed on a screen 2 m away is

• A. 1.0 mm
• B. 1.5 mm
• C. 2.0 mm
• D. 1.9 mm

Answer 1

The correct option is A 1.0 mm

We know that for Young's Double Slit Experiment

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

Here,

$\lambda =5\times {10}^{-7}{m}^{-1}D=2md={10}^{-3}m$

Now, $\beta =\frac{5\times {10}^{-7}\times 2}{{10}^{-3}}m={10}^{-3}=1.0mm$

Thus $\beta =1.0mm$