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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
What can you see in a completely dark room? If you switch on an electric bulb in this dark room as a light source, explain how you could now see:
(a) the electric bulb
(b) a piece of white paper
The optician's prescription for a spectacle lens is marked +0.5 D. What is the:
(a) nature of spectacle lens?
(b) focal length of spectacle lens?
The power of a combination of two lenses X and Y is 5 D. If the focal length of lens X be 15 cm :
(a) calculate the focal length of lens Y.
(b) state the nature of lens Y.
How is accommodation produced?
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.
Find the power of a convex lens of focal length of + 25 cm.
The power of lens depends on the focal length of the lens
Match the following:
| Column - I | Column - II | ||
| 1 | Retina | a | Path way of light |
| 2 | Pupil | b | Far point comes closer |
| 3 | Ciliary muscles | c | near point moves away |
| 4 | Myopia | d | Screen of the eye |
| 5 | Hypermetropia | e | Power of accommodation |
A point object is placed at O in front of a glass sphere as shown in figure.
Show the formation of the image by the sphere.
The power of convex lens of focal length 20 cm is ______.
