Question

If the focal length of objective lens is increased then magnifying power of

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

Answer 1

The correct option is D microscope will decrease but that of telescope increase

For microscope, Magnifying power $=\frac{LD}{f_0{f}_e}\propto \frac{1}{f_0}$

For telescope, Magnifying power $=\frac{f_0}{f_e}\propto f_0$

If the focal length of objective lens is increased then magnifying power of microscope will decrease but that of telescope increase