Optics Question 620

Question: A thin double convex lens has radii of curvature each of magnitude 40 cm and is made of glass with refractive index 1.65. Its focal length is nearly

[MP PMT 1997]

Options:

A) 20 cm

B) 31 cm

C) 35 cm

D) 50 cm

Show Answer

Answer:

Correct Answer: B

Solution:

$ f=\frac{R}{2(\mu -1)}\Rightarrow f=\frac{40}{2(1.65-1)}\approx 31 $ cm



NCERT Chapter Video Solution

Dual Pane