Question

to icrease magnifing power of telescope we should increase​

Answer 1

The focal length

So, clearly increasing the focal length of objective increases the magnifying power of the telescope. Increasing the focal length of the eye-piece decrease the magnifying power of telescope.

Answer 2

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So, clearly increasing the focal length of objective increases the magnifying power of the telescope. Increasing the focal length of the eye-piece decrease the magnifying power of telescope.