Light of wavelength 500nm is used in a double–slit arrangement in which the two slits are 0.30mm apart and the screen is placed 1.5m away from the slits.
(a) Calculate the distance on the screen between the 5th bright fringe and the 3rd dark fringe measured on the same side of the central bright fringe.
(b) Find the distance of the first dark fringe from the central bright fringe.
(c) If the entire apparatus is immersed in water of refractive index 4/3, determine the new value of the distance calculated in part (b). (Assume the wavelength in water changes accordingly.)