JEE Main 2025 Physics question
A thin plano convex lens made of glass of refractive index 1.5 is immersed in a liquid of refractive index 1.2. When the plane side of the lens is silver coated for complete reflection, the lens immersed in the liquid behaves like a concave mirror of focal length 0.2 m. The radius of curvature of the curved surface of the lens is :-
Answer: (2)
Solution
Using refraction at curved surface then reflection at silvered plane surface, combined power gives , and gives m.