If the focal length of the objective lens is increased then

Options

A. microscope will increase but that of electroscope decrease
B. microscope and telescope both will increase
C. microscope and telescope both will decrease
D. microscope will decrease but that of telescope will increase

Answer

D

Explanation

For microscope, `m=(L)/(f_(v))(D)/(f_(e)) Rightarrow m alpha (1)/(f_(v))`
`"For telescope" m=(f_(v))/(f_(e)), m alpha f_(v)`
The magnifying power of microscope will decrease but the magnifying power telescopw will increase.