When a ray of light is incident on the face AB of prism normally, after refraction it is found to graze the side AC as shown in the figure, the refractive index of the prism is

1.414

The correct answer is Option (2) → 1.414

$\text{Normal to }AC\text{ makes }45^\circ\text{ with the horizontal, so }i=45^\circ$

$n\sin i=1\Rightarrow n\sin45^\circ=1$

$n=\frac{1}{\sin45^\circ}=\frac{1}{\frac{\sqrt{2}}{2}}=\sqrt{2}$