Radius of curvature of one surface of double convex lens is three times of the other. If focal length of the lens is 30 cm and refractive index of the lens material is3/2, then radius of curvature are

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

60 cm

80 cm

40 cm

20 cm

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

$R_{1} = 3 R, R_{2} = - R, f = 30 cm, μ = \frac{3}{2}$

$\frac{1}{f} = (μ - 1) (\frac{1}{R_{1}} - \frac{1}{R_{2}})$

$\frac{1}{30} = (\frac{3}{2} - 1) (\frac{1}{3 R} + \frac{1}{R})$

$\frac{1}{30} = \frac{1}{2} \times (\frac{1 + 3}{3 R}) = \frac{1}{2} \times \frac{4}{3 R} \Rightarrow \frac{1}{30} = \frac{2}{3 R}$

$R = 20$

$Since R_{2} = 20 cm, R_{1} = 3 R = 3 (20) = 60 cm$

JEE

NEET

Foundation JEE

Foundation NEET

CBSE