(a) Explain two features to distinguish between the interference pattern in Young's double slit experiment with the difference pattern obtained due to a single slit.
(b) A monochromatic light of wavelength `500 nm` is incident normally on a single slit of width 0.2 nm of produce a diffraction pattern. Find the angular width of the central maximum obtained on the screen.
Estimate the number of fringes obtained in Young's double slit experimental with fringe width `0.5 mm`, which can be accommodated within the region of total angular spread of the central maximum due to single slit.

Explanation

(a)
(b)Angular width of central maximum in diffraction pattern
`= (2lambda)/(d) = (2 xx 500 xx 10^(-9))/(0.2 xx 10^(-3))"………."(i)`
`= 10 xx 500 xx 10^(-6) = 0.5 xx 10^(-3)m`for double slit
Number of fringe` = ("Ang. width")/("Fringe width") = (5 xx 10^(-3))/(5 xx 10^(-3)) = 10`.