A) 6.43 cm
B) -2.5 cm
C) - 22.5 cm
D) 2.66 cm
Correct Answer: C
Solution :
Since the screen has to be moved away, the lens used should be concave. \[\frac{1}{f}=\frac{1}{v}-\frac{1}{u}\] \[\Rightarrow \,\,\,\frac{1}{f}=\frac{1}{18}-\frac{1}{10}\] \[f=\frac{180}{10-18}\,\,=\,\,-22.5\,cm\]You need to login to perform this action.
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