Assuming the mean wavelength of light as `555 nm`, estimate the smallest angular separation of two stars which can be just resolved by the telescope. Given the diameter of objective of astronomical telescope is `25 cm`.

Answer

`2.7 xx 10^(-6) rad`

Explanation

Here, `lambda = 555 nm = 555 xx 10^(-9)m`
`D = 25 cm = 2 xx 10^(-2)m , d theta = ?`
`d theta = (1.22 lambda)/(D) = (1.22 xx 555 xx 10^(-9))/(25 xx 10^(-2))`
`= 2.7 xx 10^(-6)` rad