Question

The magnifying power of a compound microscope increase with

• 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 lengths of both objects and eye-piece are increased
• D. focal lengths of both objects and eye-piece are decreased

Answer 1

Answer: (D)

focal lengths of both objects and eye-piece are decreased

Answer 2

Magnifying power of compound microscope $M=-\frac{v_{t}}{u_{o}}\left(1+\frac{D}{f_{e}}\right)=-\frac{L}{f_{o}}\left(1+\frac{D}{f_{e}}\right)$