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प्रश्न
Fill in the following blank with suitable words :
The reciprocal of the focal length in metres gives you the _________ of the lens, which is measured in ___________.
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उत्तर
The reciprocal of the focal length in metres gives you the power of the lens, which is measured in dioptres.
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संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2.5 D.
Find the focal length of a lens of power −2.0 D. What type of lens is this?
A student uses a lens of focal length 40 cm and another of –20 cm. Write the nature and power of each lens
Name the physical quantity whose unit is dioptre.
Which of the two has a greater power: a lens of short focal length or a lens of large focal length?
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?
What is the nature of a lens whose power is, −4 D?
A lens has a focal length of, −10 cm. What is the power of the lens and what is its nature?
A converging lens has a focal length of 50 cm. The power of this lens is:
State the condition for the following a ray passes undeviated through the lens .
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
A screen is placed a distance 40 cm away from an illuminated object. A converging lens is placed between the source and the screen and its is attempted to form the image of the source on the screen. If no position could be found, the focal length of the lens
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.
A stick partly immersed in water appears to be bent. Draw a ray diagram to show the bending of the stick when placed in water and viewed obliquely from above.
Find the power of a convex lens of focal length of + 25 cm.
An object is placed in front of a converging lens. Obtain the conditions under which the magnification produced by the lens is
- negative and
- positive.
The focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
