A telescope uses light having wavelength `5000Å` and uses lenses of focal 2.5 cm and 30 cm. Let thediameter of the aperture of the objective is 10 cm, then what should be the resolving limit and magnifying power of the telescope respectively?

Options

A. `6.1x10^(-6)` rad and 12
B. `5.0xx10^(-6)` rad and 12
C. `6.1xx10^(-6)` rad and `8.3xx10^(-2)`
D. `5.0xx10^(-6)` rad and `8.3xx10^(-2)`

Answer

A

Explanation

Resolving limit of telescope= `(1.22 lamda)/2`,
Where a, diameter of the aperture of the objective
`=(1.22xx(5000xx10^(-10)))/0.1`
`=6.1xx10^(-6)` rad
Magnifying power of the telescope is given by (assuming image is formed at infinity)
`m=-(f_(0))/(f_(e))`
`=30/2.5`
`|m|=12`