The magnifiying power of a compound microscope increase with

Options

A. the focal length of objective lens is increased and that of eye lens is decreased
B. the focal length of eye lens is increased and that of objective lens is decreased
C. focal length of both objects and eye-piece are increased
D. focal lenghts of both objects and eye -piece are decreased.

Answer

B

Explanation

Magnifying power of compound microscope
`M = - (v_a)/(u_a)( 1 + (D)/(f_(e))) = - (L)/(f_(o)) (1 + (D)/(f_(e)))`