An astronomical refractive telescope has an objective of focal length `20 m` and an eyepiece of focal length `2 cm`.

A planet is observed by astronomical refracting telescope having an objective of focal length 16cm and an eyepiece of focal length 2cm.

A planet is observed by an astronomical refracting telescope having an objective of ofcal length 16m and an eyepiece of focal length 2 cm. Then,

A planet is observed by an astronomical refracting telescope having an objective of ofcal length 16m and an eyepiece of focal length 2 cm. Then,

A planet is observed by an astronomical reflecting telescope having an objective of focal length 16 m and eyepiece of focal length 2 cm

An astronomical telescope has an objective of focal length 20 cm and an eyepiece of focal length 4.0 cm. The telescope is focused to see an object 10 Km from the objective .The final image is formed at infinity. Find the length of the tube and the angular magnification produced by the telescope.

An astronomical telescope has an objective of focal length 100 cm and an eye piece of focal length 5 cm. The final image of a star is seen 25 cm from the eyepiece. The magnifying power of the telescope is