A) \[(n-1)F\]
B) \[(n+1)F\]
C) \[\left( \frac{n-1}{n} \right)F\]
D) \[\left( \frac{n+1}{n} \right)F\]
Correct Answer: A
Solution :
\[m=\frac{I}{O}=\frac{v}{u}=\frac{1}{n}\] \[\Rightarrow \] \[v=\frac{u}{n}\] Now, \[\frac{1}{v}-\frac{1}{u}=\frac{1}{f}\] \[\Rightarrow \] \[\frac{1}{f}=-\frac{1}{u}+\frac{n}{u}=\frac{(n-1)}{u}\] \[\therefore \] \[u=(n-1)f\]You need to login to perform this action.
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