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प्रश्न
A lens forms an upright and diminished image of an object, irrespective of its position. What kind of lens is this? Draw an outline ray diagram to show the formation of the image. State the position and one more characteristic of the image.
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उत्तर
A concave (or diverging) lens forms an upright and diminished image of an object irrespective of its position.
The outline ray diagram showing the formation of the image is given in figure. For the object AB, the image is A’B’.
The image is formed between optical centre O and focus F, in front of the lens.
The image is virtual.
संबंधित प्रश्न
Calculate the focal length of a corrective lens having power +2.5 D.
What is meant by a power of a lens? Define its SI unit.
Give the usual name for the following:
A point inside a lens through which the light passes undeviated.
The lens A has a focal length of 25 cm whereas another lens B has a focal length of 60 cm. Giving reason state, which lens has more power: A or B.
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 ___________.
Fill in the following blank with suitable word:
For converging lenses, the power is __________ while for diverging lenses, the power is ___________.
A convex lens is of focal length 20 cm. Find its power.
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.
The power of lens depends on the focal length of the lens
