Answer:
Explanation:
slit width d = .695 x 10â»Âł m
screen distance D = 2.16 m
distance of first minima x = 1.35 x 10â»Âł m
Let wave length of light used be λ
distance of first minima x = λ D / d
putting the values
1.35 x 10â»Âł  = λ x 2.16  /  .695 x 10â»Âł
λ = .4343 x 10â»â¶ m
= 434.3 x 10â»âč m
= 434.3 nm .