CameraIcon

SearchIcon

MyQuestionIcon

290

You visited us 290 times! Enjoying our articles? Unlock Full Access!

Lens Maker's Formula

A biconvex le...

Question

A biconvex lens made of glass(refractive index $1.5$ ) has two spherical surfaces having radii $20$ cm and $30$ cm. Calculate its focal length.

Open in App

Solution

Refractive index of glass $μ = 1.5$

Given : $R_{1} = 20 c m$ $R_{2} = - 30 c m$

Using lens maker formula :

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

Or $\frac{1}{f} = (1.5 - 1) (\frac{1}{20} - \frac{1}{(- 30)})$

$⟹ f = 24 c m$

Suggest Corrections

thumbs-up

0

Similar questions

Q. What is the focal length of double concave lens kept in air with two spherical surface of radii

R_{1} = 30 c m

R_{2} = 60 c m

. Take refractive index of lens as

μ = 1.5

Q. What is the focal length of double concave lens kept in air with two spherical surfaces of radii

R_{1} = 30 c m

R_{2} = 60 c m

. Take refractive index of lens with respect to surrounding as n = 1.5.

Q. Find the focal length of a lens made up of two identical spherical surfaces having radius of curvature

10 cm

and refractive index

1.5

Q. A biconvex lens in air has radii of curvature

20 c m

each. If the refractive index of the material of the lens is

1.5

, what is its focal length?

Q. A double convex lens has two surfaces of equal radii

15 cm

and refractive index

μ = 1.5

, its focal length is equal to

View More

Join BYJU'S Learning Program

similar_icon

Related Videos

lock

Thin Lenses: Point Objects

PHYSICS

Watch in App

explore_more_icon

Explore more

Lens Maker's Formula

Standard XII Physics

Join BYJU'S Learning Program

CrossIcon