Question

Why should the objective of a telescope have focal length and large apearture ? Justify your answer .

Answer 1

From `(MP)_("max") = (f_(0))/(f_(1)) (1+(f_(e))/(d))` if, `f_(o)` (focal length) is large, it enhances, the magnifying power. Large apearture helps is collecting large ammount of light making image bright.