Some water is filled in a container of height 30 cm . If is is to appear half filled to the observer when…
Some water is filled in a container of height 30 cm . If is is to appear half filled to the observer when viewed from the top of the container, the height upto which water should be filled in it, is [Refractive index of water $=\frac{4}{3}$ ]
15 cm
18 cm
20 cm
24 cm
Solution
Refractive index of a medium is given by,
n= Real depth/ Apparent depth...(i)
Given that, height of container $=30 \mathrm{~cm}$
Apparent depth $=15 \mathrm{~cm}$...(ii)
Real depth $=\mathrm{n} \times$ Apparent depth $\ldots[$ From (i) $]$
Given that, $n_w=\frac{4}{3}$...(iii)
...(iii)
Real depth $=20 \mathrm{~cm}$
...[From (ii) and (iii)]
$\therefore \quad x=20 \mathrm{~cm}$
