A) 16 cm above water level
B) 9 cm above water level
C) 24 cm below water level
D) 9 cm below water level
Correct Answer: B
Solution :
Sun is at infinity i.e. \[u=\infty \] so from mirror formula we have \[\frac{1}{f}=\frac{1}{-32}+\frac{1}{(-\infty )}\Rightarrow f=-32\]\[cm\]. When water is filled in the tank upto a height of 20 cm, the image formed by the mirror will act as virtual object for water surface. Which will form it?s image at \[I\] such that \[\frac{\text{Actual height}}{\text{Apperant height}}=\frac{{{\mu }_{w}}}{{{\mu }_{a}}}\] i.e. \[\frac{BO}{BI}=\frac{4/3}{1}\] \[\Rightarrow \] \[BI=BO\times \frac{3}{4}\]=\[12\times \frac{3}{4}=\]\[9\]\[cm\].You need to login to perform this action.
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