A) 2f
B) \[\frac{3f}{2}\]
C) \[\frac{5f}{2}\]
D) 3f
Correct Answer: B
Solution :
\[m=-(v/u)\]\[\Rightarrow \]\[-2=-v/u\] [- ve magnification because image is real] \[\Rightarrow \]\[v=2u\] From mirror formula, \[(1/v)+(1/u)=(1/f)\] \[(1/2u)+(1/u)=(1/f)\] \[\Rightarrow \]\[3/2u=1/f\]\[\Rightarrow \]\[u=3f/2\]You need to login to perform this action.
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