Advertisements
Advertisements
प्रश्न
How unit of power related to focal length of a lens?
Advertisements
उत्तर
Power is expressed as inverse of focal length, f (in metres).
`"Power (in Diopters) ="1/"Focal length (in metres)"`
APPEARS IN
संबंधित प्रश्न
Define 1 dioptre of 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?
Kavita from 10th is using spectacles. The power of the lenses in her spectacles is –2.5 dioptre. Answer the following questions:
1) Which lenses are used in her spectacles?
2) State the defect of vision Kavita is suffering from.
3) Find the focal length of the lenses used in her spectacles
Give the usual name for the following:
A point inside a lens through which the light passes undeviated.
Which of the two has a greater power: a lens of short focal length or a lens of large focal length?
What do you understand by the power of a lens? Name one factor on which the power of a lens depends.
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.
A double convex lens has two surfaces of equal radii R and refractive index \[m = 1 \cdot 5\]
A double convex lens has focal length 25 cm. The radius of curvature of one of the surfaces is double of the other. Find the radii, if the refractive index of the material of the lens is 1.5.
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.
