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AP EAMCET · PHYSICS · Ray Optics

The radius of curvature of the face of planoconvex lens is \(12 \mathrm{~cm}\) and its refractive index is 1.5. Then, the focal length of the lens is

  1. A \(26 \mathrm{~cm}\)
  2. B \(22 \mathrm{~cm}\)
  3. C \(24 \mathrm{~cm}\)
  4. D \(20 \mathrm{~cm}\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(24 \mathrm{~cm}\)

Step-by-step Solution

Detailed explanation

Given, refractive index of lens, \(\mu=1.5\) Radius of curved face, \(R_1=12 \mathrm{~cm}\) Radius of plane face, \(R_2=\infty\) Now, using the expression of focal length, \[ \frac{1}{f}=(\mu-1)\left[\frac{1}{R_1}-\frac{1}{R_2}\right] \] Substituting the values, we get…