Advertisements
Advertisements
प्रश्न
The focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
Advertisements
उत्तर
`1/"f" = ("n"-1) (1/"r"_1 + 1/"r"_2)`
`1/"f" = ("n"-1) (1/"f" + 1/"f")`
`("n"-1) = 1/2`
∴ n = 1.5
APPEARS IN
संबंधित प्रश्न
Define the power of a lens.
A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
Which type of lens has (a) a positive power, and (b) a negative power?
The power of a lens is + 0.2 D. Calculate its focal length.
An object of height 4 cm is placed at a distance of 15 cm in front of a concave lens of power, −10 dioptres. Find the size of the image.
A converging lens has a focal length of 50 cm. The power of this lens is:
A diverging lens has a focal length of 0.10 m. The power of this lens will be:
On reducing the focal length of a lens, its power ______.
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
Complete the diagram to show the formation of the image of the object AB.
(i) Name the Lens LL’.
(ii) Where is the image of the object AB formed?
(iii) State three characteristics of the image.
