In a Young's double slit experiment set up, the two slits are kept 0.4 mm apart and screen is placed at 1 m from slits. If a thin transparent sheet of thickness 20 is introduced in front of one of the slits then center bright fringe shifts by 20 mm on the screen. The refractive index of transparent sheet is given by 10, where is .
Answer
14
Solution
Shift of the fringe pattern due to a sheet of thickness t: y = ( - 1)tDd
20 10-3 = ( - 1) 20 10-6 10.4 10-3
20 10-3 = ( - 1) 5 10-2
- 1 = 0.4 = 1.4 = 1410
= 14
Answer: 14