Question

# Double convex lenses are to be manufactured from a glass of refractive index 1.55, with both faces of same radius of curvature. What is the radius of curvature required if the focal length is to be 20 cm?

A
11 cm
B
22 cm
C
7 cm
D
6 cm
Solution
Verified by Toppr

#### Lens maker's formula,1f=(μ−1)(1R1−1R2)Here, f = 20 cm, μ = 1.55, R1 = R, R2 = -R120=(1.55−1)(1R−1(−R))or120=0.55×2R⇒R=1.1×20=22cm

17
Similar Questions
Q1

(a) Monochromatic light of wavelength 589 nm is incident from air on a water surface. If p for water is 1.33, find the wavelength, frequency and speed of the refracted light.
(b) A double convex lens is made of a glass of refractive index 1.55, with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is 20 cm.

View Solution
Q2

(a) Monochromatic light of wavelength 589 nm is incident from air on a water surface. If p for water is 1.33, find the wavelength, frequency and speed of the refracted light.
(b) A double convex lens is made of a glass of refractive index 1.55, with both faces of the same radius of curvature. Find the radius of curvature required, if the focal length is 20 cm.

View Solution
Q3

A double convex lens has a focal length of 40 cm. If the radius of curvature of its refracting surfaces are 10 cm and 20 cm, find the refractive index of the material of the lens.

View Solution
Q4

The radius of curvature for a convex lens is 40 cm. If its refractive index is 1.5, the focal length will be __________.

View Solution
Q5

Double-convex lenses are to be manufactured from a glass ofrefractive index 1.55, with both faces of the same radius ofcurvature. What is the radius of curvature required if the focal lengthis to be 20cm?

View Solution
Solve
Guides