Question

The magnifying power of an objective lens of a compound microscope is 8 if the magnifying power of the compound microscope is 32. Then calculate magnifying power of an eyepiece lens.

Answer 1

Hint: We know that magnifying power of a compound microscope is a combination of magnifying power of two lenses. This can be given mathematically as, $M={{m}_{o}}\times {{m}_{e}}$. Using this formula, we will find the value of magnifying power of an eyepiece lens

Formula used: $M={{m}_{o}}\times {{m}_{e}}$

Complete step by step answer: In question it is given that the magnifying power of an objective lens of a compound microscope is 8 if the magnifying power of the compound microscope is 32. So, first of all we will understand the magnifying power of a compound microscope.

Magnification power of compound microscope is combination of magnification of two lenses i.e. objective lens eyepiece lens. The magnification of a compound microscope is a product of magnification of an objective lens and magnification of eyepiece lens. It can be given mathematically as,

$M={{m}_{o}}\times {{m}_{e}}$
Where, ${{m}_{o}}$ is magnification of an objective lens and ${{m}_{e}}$ is magnification of an eyepiece lens.

Now, in question we are given the magnification of objective lens is 8 and magnifying power of microscope is 32, this can be given mathematically as,

${{m}_{o}}=32$
$M=8$

So, on substituting this value in equation we will get,

$32=8\times {{m}_{e}}$
${{m}_{e}}=\dfrac{32}{8}=4$
Hence, the magnification of eyepiece lenses is 4.

Note: Many times students consider eyepiece lenses as objective lenses or vice versa, but the simplest method to remember is that the lens which is near to the eye of an observer or human is called an eyepiece lens and the lens which is near to the object is called an objective lens. In this way students can easily remember the difference between them and solve the problems easily.
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