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 \(\left(\sin 45^{\circ}=\frac{1}{\sqrt{2}}, \sin 90^{\circ}=1\right)\)

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.