An object is fixed at the bottom of a vessel and water is filled in the vessel upto a height of \(10 \mathrm{~cm}\). A plane mirror is placed at a height of \(7 \mathrm{~cm}\) from the surface of water in such a way that its reflecting surface faces the water. The distance of the image from the mirror is (Refractive index of water, \(n=1.33\) )

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.