The objective of a telescope has a diameter of `125 cm`. Calculate the smallest angular separation of two stars that may be resolved by it. Wavelengthof light used is `6000 Å`.

Answer

`0.12 sec. of arc`

Explanation

Here, `D = 125 cm = 1.25 m, d theta = ?`
`lambda = 6000 Å = 6 xx 10^(-7)m`
`d theta = (1.22 lambda)/(D) = (1.22 xx 6 xx 10^(-7))/(1.25)rad`
`= 5.856 xx 10^(-7) rad`.
`= 5.856 xx 10^(-7) xx (180)/(pi) xx 60 xx 60 sec. of arc`.
`= 0.12` sec. of arc.