What is the minimum distance between two points which can be resolved at 2 km using a terrestrial telescope with an objective of diameter 8 cm using light of wavelength 600 nm ?
What is its resolving power ?

Explanation

`x=2000m, a=8 times10^-2m,lamda=600 nm`
`=600 times10^-9 m`
Limited of resolution, `d theta`
`(1.22 lamda)/a=(1.22 times600 times10^-9)/(8 times10^-2)=9.15 times10^-6 radian`
We have `y= x times d theta=2000 times 9.15 times 10^-6`
`=1.83 times 10^-2 m`
Resolving power
`=1/(d theta)=1/(9.15 times10^-6)=1.09 times10^5`
Result:Minimum distance between two points can be just revolved =`1.83 times 10^-2 m` Resolving power of the telescope =`1.09 times 10^5`.