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प्रश्न
Which type of lens has a positive power?
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उत्तर
A convex lens has positive power.
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संबंधित प्रश्न
What is meant by a power of a lens? Define its SI unit.
Define 1 dioptre of power of a lens.
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The lens mentioned in 6(b) above is of focal length 25cm. Calculate the power of the lens.
The lens A has a focal length of 25 cm whereas another lens B has a focal length of 60 cm. Giving reason state, which lens has more power: A or B.
A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with one another.
(a) What is the power of this combination?
(b) What is the focal length of this combination?
(c) Is this combination converging or diverging?
Define the term focal length of a lens.
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Complete the diagram to show the formation of the image of the object AB.
(i) Name the Lens LL’.
(ii) Where is the image of the object AB formed?
(iii) State three characteristics of the image.
If the lens is of focal length 25 cm. Calculate the power of the lens.
Assertion and reasoning type
- Assertion: Myopia is due to the increase in the converging power of eye lens.
- Reason: Myopia can be corrected with the help of concave lens.
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