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प्रश्न
On reducing the focal length of a lens, its power ______.
विकल्प
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
Define the power of a lens.
Define 1 dioptre of power of a lens.
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
A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens
Define the term focal length of a lens.
A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.
The power of lens depends on the focal length of the lens
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 ______.
An object is placed in front of a converging lens. Obtain the conditions under which the magnification produced by the lens is
- negative and
- positive.
When monochromatic red light is used instead of blue light in a convex lens, its focal length will ______.
