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प्रश्न
State the condition for the following a ray passes undeviated through the lens .
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उत्तर
If a ray passes undeviated through the lens it is incident at the optical centre of the lens.
संबंधित प्रश्न
Find the power of a concave lens of focal length 2m.
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.
Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.
The power of a lens is, −2 D. What is its focal length?
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 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.
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 |
Define power of a lens. What is its unit? One student uses a lens of focal length 50 cm and another of –50 cm. What is the nature of the lens and its power used by each of them?
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.
In what unit is the power of a lens expressed?
