Question

A telescope of objective lens diameter 2 m uses light of wavelength 5000 Å for viewing stars. The minimum angular separation between two stars whose image is just resolved by their telescope is ______.

Options

• 4 × 10^-4 rad 

• 0.25 × 10^-6 rad 

• 0.31 × 10^-6 rad 

• 5 × 10^-3 rad

Answer 1

A telescope of objective lens diameter 2 m uses light of wavelength 5000 Å for viewing stars. The minimum angular separation between two stars whose image is just resolved by their telescope is 0.31 × 10^-6 rad.

Explanation:

`Delta theta = (1.22  lambda)/"a" = (1.22 xx 5 xx 10^-7)/2`

`= 0.31 xx 10^-6` rad