An astronomical refractive telescope has an objective of focal length 20 m and eye piece of focal length 2 cm

Question

$\begin{array}{1 1} \text{The length of the telescope is 20.02m} \\ \text{The ,magnification is 1000} \\ \text{The image formed is inverted} \\ \text{An objected of a larger aperture will increase the brightness and reduce chromatic aberration of the image } \end{array}$