Snell's law of refraction

A ray of light traveling through medium $\text{A}$‍ is incident on another medium $\text{B}$‍, where it refracts making an angle of $60\mathrm{°}$‍ with the normal.

The refractive index of medium $\text{B}$‍ with respect to medium $\text{A}$‍, $n_{\text{BA}}=\sqrt{{\displaystyle \frac{2}{3}}}$‍.