Least distance of distinct vision is 25 cm. What will be magnifying power of simple microscope of focal length 5 cm, if final image is formed at minimum distance of distinct vision?
Given,
Focal length of convex lens, f=5cm
Position of image, v=25cm
Position of object, u=?
Apply lens formula
1f=1v−1u
15=125−1u
u=254cm
Magnifying power of instrument:
M=1+Df
M=1+255=6
Hence, object distance is 254cm and magnifying power is 6