Question

vertical poles are at distance of 6.28m. from each other, what should the maximum distance of an observer from poles to see them separately :- (Limiting angle of resolution of eye is )(1)21.6 km(2)10.8 km(3)15 km(4)25.2 km​

Answer 1

Given;-

Distance = 6.28m = x

Limiting resolution of eye = 1' or 0.0003 radians =  θ

To find;-

Distance between the poles (d)

Solution;-

Appling the Rayleigh criterion,

θ = 1.22 λ/D = $\frac{x}{d}$

⇒d = x/θ = 6.28/0.0003 ≈ 21.6km

Hence, the maximum distance from the observer is 21.6m