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प्रश्न
The power of a lens is + 1.0 D is :
पर्याय
convex of focal length 1.0 cm
convex of focal length 1.0 m
concave of focal length 1.0 cm
concave of focal length 1.0 m
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उत्तर
Power of a lens is +1.0 D. The positive sign indicates that the focal length of the lens is positive which indicates the lens is a convex lens.
Power is P = `1/("f" ("in" "m"))`
+ 1.0 D = `1/("f" ("in" "m"))`
∴ f = 1.0 m
Hence, the correct answer is convex of focal length 1.0 m.
संबंधित प्रश्न
Define 1 dioptre of power of a lens.
Consider two statements A and B given below:
A: real image is always inverted
B: virtual image is always erect
Out of these two statements:
Name the physical quantity whose unit is dioptre.
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 power of a lens. Write its units. Deduce the relation `1/f =1/f_1 +1/f_2`for two thin lenses kept in contact coaxially.
Consider the situation described in the previous problem. Where should a point source be placed on the principal axis so that the two images form at the same place?
If there is a convex lens of focal length 75 cm and a concave lens of focal length 40 cm, then calculate their combined power and combined focal length.
When monochromatic red light is used instead of blue light in a convex lens, its focal length will ______.
The power of convex lens of focal length 20 cm is ______.
In what unit is the power of a lens expressed?
