Physics

Problem

Light of wavelength

650\,\text{nm}

falls on two slits separated by

0.40\,\text{mm}

. The screen is kept

2.0\,\text{m}

away from the slits. a. (i) Obtain the expression for the fringe width

\beta

for this arrangement. b. (ii) Using your result, calculate the distance between the

3

rd bright fringe and the

5

th bright fringe on the same side of the centre. c. (iii) If the experiment is now performed in water of refractive index

4/3

(all geometrical distances remaining unchanged), find the new value of the distance calculated in part (ii).