Ray Optics

A ray of light is incident on first face of an equilateral glass prism at an angle of incidence ' $I$ '. The emergent ray just grazes along the adjacent face. The refractive index of the the prism is $\sqrt{2}$. The value of angle of incidence at first face is $\left(\sin 45^{\circ}=\frac{1}{\sqrt{2}}, \sin 90^{\circ}=1\right)$