Question

How much water should be filled in a container $21\, cm$ in height, so that it appears half filled when viewed from the top of the container? (given that $\mu_{ w }=4/3$ )

• A. 8.0 cm
• B. 10.5 cm
• C. 12.0 cm
• D. None of the above

Answer 1

Answer: (C)

To see the container half-filled from top, water should be filled up to height $x$ so that bottom of the container should appear to be raised upto height $(21-x)$.As shown in figure apparent depth $h^{\prime}=(21-x)$ Real depth $h=x$

$\therefore \mu=\frac{h}{h^{\prime}} \Rightarrow \frac{4}{3}$
$=\frac{x}{21-x} \Rightarrow x=12\, cm$