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प्रश्न
How is the power of a lens related to its focal length?
उत्तर
The power of a lens is related to the focal length as:
Power (P)=`I/f'`
where, f is measured in metres and P in dioptres.
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संबंधित प्रश्न
(a) At what distance should the lens be held from the figure in order to view the squares distinctly with the maximum possible magnifying power?
(b) What is the magnification in this case?
(c) Is the magnification equal to the magnifying power in this case? Explain.
Ranbir claims to have obtained an image twice the size of the object with a concave lens. Is he correct? Give a reason for your answer.
Name the physical quantity whose unit is dioptre.
How is the power of a lens related to its focal length?
How is the sign (+ or -) of power of a lens related to its divergent or convergent action?
Name the type of lens whose power is positive.
The image of an object formed by a lens is real, inverted and of the same size as the object. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens ? Draw ray diagram to justify your answer.
What is meant by the power of accommodation produced?
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 kept at a distance of 1m from a lens of power +2D:
- Identify the type of lens.
- Calculate its focal length and distance of the image formed.
