# A coin lies at the bottom of a tank filled with two immissible liquid. Liquid 1 on top is $20\;cm$ layer thick of refractive index $\mu_1 =1.33$ and liquid 2 is $40\;cm$ thick with refractive index $\mu_2=1.46$. At what depth below the surface the coin appear?

$(a)\;60\;cm \\ (b)\;48\;cm \\ (c)\;50\;cm \\ (d)\;42\;cm$

when multiple layers of liquid of height $h_1$ and $h_2$ of refractive index $\mu_1$ and $\mu_2$ respectively are present in tank and an object at the bottom is viewed from top . then ,
apparent depth $= \large\frac{h_1}{\mu _1} +\frac{h_2}{\mu_2}$
$\therefore$ apparent depth $=\large\frac{20}{1.33} +\frac{40}{1.46}$
$\qquad= 42 \;cm$
Hence d is the correct answer