A) -10 cm.
B) -10/4 cm.
C) -10/3 cm.
D) None
Correct Answer: C
Solution :
\[\frac{1}{f}=(\mu -1)\left( \frac{1}{{{R}_{1}}}-\frac{1}{R\to } \right)\]\[R=10\,cm.\] \[f'=(3-1)\left( \frac{1}{-10}-\frac{1}{10} \right)\] \[=-\frac{10}{4}\] \[\frac{1}{{{f}_{eq}}}=\frac{1}{20}-\frac{4}{10}+\frac{1}{20}=\frac{2}{20}-\frac{4}{10}\] \[\Rightarrow {{f}_{eq}}=-\frac{10}{3}cm\]You need to login to perform this action.
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