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प्रश्न
On reducing the focal length of a lens, its power ______.
पर्याय
Decreases
Increases
Does not change
First increases then decreases.
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उत्तर
On reducing the focal length of a lens, its power increases.
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संबंधित प्रश्न
State power of a lens S.I. unit.
Define 1 dioptre of power of a lens.
Define the term focal length of a lens.
How is the power of a lens related to its focal length?
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 screen is placed a distance 40 cm away from an illuminated object. A converging lens is placed between the source and the screen and its is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens
Surabhi from std. X uses spectacle. The power of the lenses in her spectacle is 0.5 D.
Answer the following questions from the given information:
- Identify the type of lenses used in her spectacle.
- Identify the defect of vision Surabhi is suffering from.
- Find the focal length of the lenses used in her spectacle.
A lens forms an upright and diminished image of an object, irrespective of its position. What kind of lens is this? Draw an outline ray diagram to show the formation of the image. State the position and one more characteristic 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 ______.
The power of convex lens of focal length 20 cm is ______.
