A ray of light travels from air to water to glass and again from glass to air. Refractive index of water w.r…
A ray of light travels from air to water to glass and again from glass to air. Refractive index of water w.r.t. air is ' $\mathrm{X}$ ', glass w.r.t. water is ' $Y$ and air w.r.t. glass is ' $\mathrm{Z}$ '. Which one of the following is correct?
$Y Z=X$
$X Y Z=1$
$X Y=Z$
$X Z=Y$
Solution
$\begin{aligned} & X=\frac{v_a}{v_w}, Y=\frac{v_w}{v_g}, Z=\frac{v_g}{v_a} \\ & \therefore X Y Z=1\end{aligned}$