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Ray Optics and Optical Instruments — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsRay Optics and Optical Instruments2 Marks
Question
Define lens and write its formula.
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Answer

Any transparent medium surrounded by two surfaces, one of which or both surfaces are spherical is called lens. There are two types of lenses-(1) Convex lens (2) Concave lens.
The relationship between the distances of the object, the distance of the image and the focal length of the lens is called lens formula. i.e., $-\frac{1}{u}+\frac{1}{v}=\frac{1}{f}$.

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