A) 12
B) 11
C) 10
D) 13
Correct Answer: A
Solution :
The following ray diagram shows the formation of image by a compound microscope. Given, \[{{f}_{e}}=10\,cm,{{f}_{o}}=4\,cm,{{u}_{o}}=-5\,cm,\] \[D=20\text{ }cm\] For objective lens \[\frac{1}{{{f}_{o}}}=\frac{1}{{{v}_{o}}}-\frac{1}{{{u}_{o}}}\] \[\frac{1}{4}=\frac{1}{{{v}_{o}}}-\frac{1}{-5}\] \[\Rightarrow \] \[\frac{1}{{{v}_{o}}}=\frac{1}{4}-\frac{1}{5}=\frac{1}{20}\] \[\Rightarrow \] \[{{v}_{o}}=20\,cm\] Magnification, \[M=-\frac{{{v}_{o}}}{{{u}_{o}}}\left( 1+\frac{D}{{{f}_{e}}} \right)\] \[=\frac{20}{-5}\left( 1+\frac{20}{10} \right)\] \[=4(1+2)=12\]You need to login to perform this action.
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