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A spherical surface separates two media of refractive indices 1 and 1.5 as shown in figure. Distance of the image of an object 'O', is
(C is the center of curvature of the spherical surface and R is the radius of curvature)

Asked in JEE Main 2nd April 1st Shift 2025 · Single spherical surface

Figure: Single spherical surface
Answer: (2) 0.4 m left to the spherical surface

Step-by-step solution

Light goes from medium 1 (n₁=1) to medium 2 (n₂=1.5); C lies in medium 2, so R=+0.4 m.

Object distance u=-0.2 m.

(n₂)/v-(n₁)/u=(n₂-n₁)/R gives (1.5)/v+1/(0.2)=(0.5)/(0.4)=1.25.

(1.5)/v=1.25-5=-3.75, so v=-0.4 m.

Negative v: virtual image 0.4 m to the left of the surface.

Why the other options are wrong

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