Question

When a container is completely filled with water $(n_w=4/3)$ its bottom appears raised by 4 cm. Find the actual depth of water.

• A. 4 cm
• B. 8 cm
• C. 12 cm
• D. 16 cm

Answer 1

Answer: (D)

16 cm

let the actual depth of water in container is $d_{actual}$

then apparent depth of water in container is $d_{apparent}$

$d_{apparent}$ = $d_{actual}-4$

the relation between refractive index and depth is

$refractiveindex=\frac{actualdepth}{apparentdepth}$

$\mu =\frac{d_{actual}}{d_{apparent}}$

$\frac{4}{3}=\frac{d_{actual}}{d_{actual}-4}\Rightarrow d_{actual}=16cm$

Hence the actual depth of water is 16 cm.