ExamBro
ExamBro
CUET · PHYSICS · PYQ PAPER 2023

The radius of curvature of each surface of a double convex lens is 15 cm and the refractive index of the medium of the lens is 1.5. What is the focal length of the lens?

  1. A 7.5 cm
  2. B 15 mm
  3. C 30 cm
  4. D 15 cm
Verified Solution

Answer & Solution

Correct Answer

(A) 7.5 cm

Step-by-step Solution

Detailed explanation

\(\frac{1}{f} = (n - 1) \left( \frac{1}{R_1} - \frac{1}{R_2} \right)\) \(\frac{1}{f} = (1.5 - 1) \left( \frac{1}{15 \text{ cm}} - \frac{1}{-15 \text{ cm}} \right)\) \(\frac{1}{f} = 0.5 \left( \frac{2}{15 \text{ cm}} \right)\) \(\frac{1}{f} = \frac{1}{15 \text{ cm}}\)…