A lens of large focal length and large aperture is best suited as an objective of an astronomical te

Question

A lens of large focal length and large aperture is best suited as an objective of an astronomical telescope since\

Professor PC Thomas Classes · Answer

(d) : As the focal length is large so, it enhances the magnifying power of telescope. The large aperture or diameter\ of lens helps in collecting large amount of light from the object so that the image formed is bright.\ The resolving power of telescope is $ 	ext { R.P. }=\frac{D}{1.22 \lambda} $ where, $D$ is diameter or aperture of lens and $\lambda$ is wavelength of light used. So, all options are correct.\