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 ${}_{\alpha }{\mu }_{\omega }=\frac{4}{3}$)

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

Answer 1

The correct option is C 12.0 cm

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'=(21-x)
Real depth h=x


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