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
Calculate the focal length of a corrective lens having power +2.5 D.
Find the focal length of a lens of power −2.0 D. What type of lens is this?
Name the physical quantity whose unit is dioptre.
Which of the two has a greater power: a lens of short focal length or a lens of large focal length?
Two lenses A and B have focal lengths of +20 cm and, −10 cm, respectively.
(a) What is the nature of lens A and lens B?
(b) What is the power of lens A and lens B?
(c) What is the power of combination if lenses A and B are held close together?
The power of a lens is + 1.0 D is :
A symmetric double convex lens is cut in two equal parts by a plane containing the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be
Which lens has more power a thick lens or a thin lens?
The above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.
A convex lens with radii of curvature R1 = R2 is immersed in water. Assuming that the refractive indices of glass and water are 3/2 and 4/3 respectively, its focal length f1 in comparison to that in air, f, is ______.
