Q. Two slits 0.3 mm separately are illuminated by light of wavelength 4500 0A. The screen is placed at a distance 1m from the slits. Find the separation among the second bright fringe on both sides of the central maximum.
Data : d = 0.3 mm = 0.3 × 10-3 m ; λ = 4500 Å = 4.5 × 10-7 m,
D = 1 m ; n = 2 ; 2x = ?
2x = ( 2 D X nλ) / d
= 2 X1 X 2 X 4.5 X 10-7 / 0.3 X 10-3
∴ 2x = 6 × 10-3 m (or) 6 mm