Answer:
d. 629 nm
Explanation:
slit separation d = .16 x 10⁻³ m
distance of screen D = 1.4 m
distance of second bright band = 11 x 10⁻³
distance of second bright band = 2 x band width
= 2 x λ D /d
Putting the values given ,
11 x 10⁻³ = 2 x λ x 1.4 / .16 x 10⁻³
λ = 1.76 x 10⁻⁶ / 2.8
= .6285 x 10⁻⁶
= 628.5 x 10⁻⁹
= 629 nm approx .
