COMEDK · Physics · 25. Ray Optics
A thin plano-convex lens acts like a concave mirror of focal length \(0.2 \mathrm{~m}\) when silvered from its plane surface. The refractive index of the material of the lens is \(1.5\). The radius of curvature of the convex surface of the lens will be
- A \(0.4 \mathrm{~m}\)
- B \(0.2 \mathrm{~m}\)
- C \(0.1 \mathrm{~m}\)
- D \(0.75 \mathrm{~m}\)
Answer & Solution
Correct Answer
(C) \(0.1 \mathrm{~m}\)
Step-by-step Solution
Detailed explanation
Resultant focal length \((f)\) of the given combination is \(0.2 \mathrm{~m}\). Refractive index of the material, \(\mu=1.5\) From the lens Maker formula, we get \[ \frac{1}{f}=(\mu-1)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right) \] where, \(R_{1}\) is the radius of curvature of…
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