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प्रश्न
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.
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उत्तर
No, he is not correct.
Reason: Magnified image of an object cannot be formed by a concave lens ever. Because, no matter where the object is placed in front of a concave lens, it always forms a virtual, erect, and diminished image of the object.
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संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2D.
A diverging lens has focal length of 3 cm. Calculate the power.
The optician's prescription for a spectacle lens is marked +0.5 D. What is the:
(a) nature of spectacle lens?
(b) focal length of spectacle lens?
An object of height 4 cm is placed at a distance of 15 cm in front of a concave lens of power, −10 dioptres. Find the size of the image.
The power of a lens is +2.0D. Its focal length should be :
On reducing the focal length of a lens, its power ______.
Consider three converging lenses L1, L2 and L3 having identical geometrical construction. The index of refraction of L1 and L2 are \[\mu_1 \text{ and } \mu_2\] respectively. The upper half of the lens L3 has a refractive index \[\mu_1\] and the lower half has \[\mu_2\] following figure . A point object O is imaged at O1 by the lens L1 and at O2 by the lens L2placed in same position. If L3 is placed at the same place,
(a) there will be an image at O1
(b) there will be an image at O2.
(c) the only image will form somewhere between O1 and O2
(d) the only image will form away from O2.
The power of lens depends on the focal length 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.
In what unit is the power of a lens expressed?
