JEE Mains · Physics · STD 12 - 9. Ray optics and optical instruments
A convex lens is made from glass material having refractive index of \(1.4\) with same radius of curvature on both sides. The ratio of its focal length and radius of curvature is ______.
- A \(0.5\)
- B \(2.5\)
- C \(0.8\)
- D \(1.25\)
Answer & Solution
Correct Answer
(D) \(1.25\)
Step-by-step Solution
Detailed explanation
Using the lens maker's formula: \(\dfrac{1}{f} = (\mu - 1) \left( \dfrac{1}{R_1} - \dfrac{1}{R_2} \right)\) For an equiconvex lens, \(R_1 = R\) and \(R_2 = -R\). Given \(\mu = 1.4\): \(\dfrac{1}{f} = (1.4 - 1) \left( \dfrac{1}{R} - \dfrac{1}{-R} \right)\)…
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