Question

A laser beam of wavelength 600 nm is incident on two slits that are separated by 0.02 mm. What is the separation between adjacent bright maxima observed on a screen 5 m away?(A) 1.1 mm (B) 0.625 mm (C) 20 mm (D) 15 cm (E) 0.1 mm

Answer 1

option D

Step-by-step explanation:

given,

wavelength = 600 nm

width of separation = 0.02 mm

L = 5 m

for mth order maxima

`d * (y_m)/(L)=m\lambda`

for (m+1)th order maxima

`d * (y_(m+1))/(L)=(m+1)\lambda`

now,

`y_m=(mL\lambda)/(d)` and

`y_(m+1)=((m+1)L\lambda)/(d)`

hence,

`\Delta y = y_(m+1) - y_m`

`\Delta y =(L\lambda)/(d)`

`\Delta y =(5 * 600 * 10^(-9))/(0.02 * 10^(-3))`

`\Delta y =0.15\ m`

`\Delta y =15\ cm`

hence, the correct answer is option D