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A concave lens and a convex mirror both are dipped in an oil of refractive index 1.2. The focal length of: |
both lens and mirror will remain the same mirror will change but of lens will remain the same lens will change but of mirror will remain same both the lens and the mirror will change |
lens will change but of mirror will remain same |
The correct answer is Option (3) → lens will change but of mirror will remain same The focal length of a mirror is determined solely by its radius of curvature (R) - $R=\frac{f}{2}$ Since mirrors rely refraction unlike lens, the refractive index of a medium has no effect on the focal lenght. |
