The separation between the objective and the eyepiece of a compound microscope can be adjusted between 98 cm to 118 cm. If the focal lengths of the objective and the eyepiece are 10 cm and 6 cm respectively, find the range of the magnifying power if the image is always needed at 24 cm from the eye.
Given data-
Focal length of the objective,
Focal length of the eyepiece,
Image distance from the eyepiece,
Distance between the objective and the eyepiece = 9.8 cm to 11.8 cm
Using lens formula
For eyepiece-
cm
1. When the separation between the objective and the eyepiece = 9.8 cm
for the objective lens, the image will be at a distance
Using lens formula for the objective lens –
Magnifying power of the compound microscope can be calculated as -
When the separation between the objective and the eyepiece is 11.8 cm
Using lens formula for the objective lens –
Magnifying power of the compound microscope can be calculated as -
Hence the magnification lies in the range of 20-30