Answer:
θ = 1.21 10⁻² rad
Step-by-step explanation:
The double slit experiment is described for constructive interference
d sin θ = m λ
where d is the separation between the slits, λ the wavelength used, m a stereo that represents the order of interference
The first order of interference corresponds to m = 1 and the separation of the slits is d = 5.2 10⁻⁵ m
sin θ = m λ / d
θ = sin⁻¹ (m λ / d)
let's calculate
θ = sin⁻¹ (1 631 10⁻⁹ / 5.2 10⁻⁵)
θ = 1.21 10⁻² rad