A) 9 cm
B) - 18 cm
C) - 9 cm
D) 18 cm
Correct Answer: D
Solution :
\[\frac{1}{F}=\frac{1}{{{f}_{1}}}+\frac{1}{{{f}_{2}}}\Rightarrow \frac{1}{F}=\frac{1}{(+18)}\Rightarrow F=18\,cm\]You need to login to perform this action.
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