The magnifying power of a small telescope is 20 and the separation between its objective and eye piece is 42 cm in normal setting.
(a) Focal length of objective is 40 cm and eyepiece is 2 cm
(b) Focal length of objective is 2 cm and eyepiece is 40
(c) To get maximum magnification from the telescope, length of tube should decrease
(d) To get maximum magnification from the telescope, length of tube should increase
