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प्रश्न
State the condition for the following a lens has both its focal lengths equal .
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उत्तर
If a lens has both its focal length equal medium is same on either side of lens.
संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2.5 D.
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.
(a) At what distance should the lens be held from the figure in order to view the squares distinctly with the maximum possible magnifying power?
(b) What is the magnification in this case?
(c) Is the magnification equal to the magnifying power in this case? Explain.
Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.
The focal length of a convex lens is 25 cm. What is its power?
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.
A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.
The power of convex lens of focal length 20 cm is ______.
A concave lens is a diverging lens whose focal length and power are both:
A concave lens has:
