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प्रश्न
What does sign of power (+ve or –ve) indicate?
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उत्तर
Positive power (+ve) of a lens indicates converging ability of a lens as in the case of convex lens, and negative power (−ve) of a lens indicates its diverging ability as in the case of concave lens.
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संबंधित प्रश्न
How unit of power related to focal length of a lens?
A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens
How is the power of a lens related to its focal length?
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.
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.
A pin of length 2.00 cm is placed perpendicular to the principal axis of a converging lens. An inverted image of size 1.00 cm is formed at a distance of 40.0 cm from the pin. Find the focal length of the lens and its distance from the pin.
How is accommodation produced?
Find the power of a convex lens of focal length of + 25 cm.
The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is ______ cm.
1 D is equivalent to:
