In a double-slit experiment, each and every slit consists of a width of 0.02 mm and they are spaced 0.14 mm apart. The pattern of light if a coherent 550 nm beam is incident on the slits is viewed on a screen 4 m away.
(i) Determine the spacing among interference fringes on the screen.
(ii) Determine the full width of the central diffraction maximum on the screen.
(iii) Determine how many fringes are visible in the central diffraction maximum?
(iv) What happens to the pattern when the whole apparatus is immersed in water? Determine new answers to each of the above parts.