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प्रश्न
The power of lens depends on the focal length of the lens
पर्याय
True
False
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उत्तर
True
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संबंधित प्रश्न
How unit of power related to focal length of a lens?
Find the focal length of a lens of power −2.0 D. What type of lens is this?
What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.
What is the nature of a lens whose power is, −4 D?
A convex lens of power 5 D and a concave lens of power 7.5 D are placed in contact with each other. What is the :
(a) power of this combination of lenses?
(b) focal length of this combination of lenses?
Two lenses A and B have focal lengths of +20 cm and, −10 cm, respectively.
(a) What is the nature of lens A and lens B?
(b) What is the power of lens A and lens B?
(c) What is the power of combination if lenses A and B are held close together?
How does focal length of a lens change when red light incident on it is replaced by violet light? Give reason for your answer.
The above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.
The focal length of a concave lens is 20 cm. The focal length of a convex lens is 25 cm. These two are placed in contact with each other. What is the power of the combination? Is it diverging, converging or undeviating in nature?
For a lens with \[f = +12\,cm\], \[R_1 = +10\,cm\] and \[R_2 = -15\,cm\], the lens maker's formula \[\frac{1}{f}=(n-1)\left(\frac{1}{R_1}-\frac{1}{R_2}\right)\] gives the refractive index of the glass as:
