A compound microscope has a magnifying power 30. The focal length of its eyepiece is 5cm. Assuming the final image to be at a least distance of distinct vision (25cm) calculate the magnification produced by objective.

A compound microscope has a magnifying power 30. The focal length of i

1.	A compound microscope has a magnifying power 30. The focal length of its eyepiece is 5cm. Assuming the final image to be at a least distance of distinct vision (25cm) calculate the magnification produced by objective.
Answer» Solution :In CASE of compound microscope `M=m_0 times m_e`…….(1) And in case of final image at least distance of distinct vision `m_e=[1+D/f.]` So from eqs. (1) and (2) `M=m_0[1+D/f]` Here M=-30, D=25cm and `f_e=5cm` So, `-30=m_0[1+25/5]` i.e., `m_0=(-30)/6=-5` Negative sign implies that image FORMED by OBJECTIVE is INVERTED.