Answer:
λ = 596 nm.
Explanation:
Fringe width = λ D / d
λ is wave length , D is screen distance and d is slit separation.
Putting the values
1.62 x 10⁻² =( λ x 5.3 ) / .195 x 10⁻³
[tex]\lambda=\frac{1.62\times10^{-2}\times195\times10^{-6}}{5.3}[/tex]
λ = 596 nm.