Answer:
1.64 * 10^(-5) m
Explanation:
Parameters given:
Angular separation, θ = 0.018 rad
Wavelength, λ = 589 nm = 5.89 * 10^(-7) m
The angular separation when there are 2 slots is given as
θ = λ/2d
where d = separation between slits
d = λ/2θ
d = (589 * 10^(-9))/(2 * 0.018)
d = 1.64 * 10^(-5) m