In a double slit experiment, when one of the slits is covered by a transparent mica sheet of refractive index 1.56, the central fringe shifts to the position of 7th bright fringe, obtained with both slits uncovered. If the light source wavelength is 450 nm, the thickness of mica sheet is 10-9 m. The value of is .
Answer
5625
Solution
The mica sheet adds an optical path ( -1)t; the central fringe shifts to the 7th bright fringe:
( -1)t=7
t= 7 450 10-91.56-1= 3150 10-90.56
t=5625 10-9 m
=5625
Answer: 5625