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प्रश्न
Distinguish between concave and convex lens.
उत्तर
| Convex lens | Concave lens |
| 1. A convex lens is thicker in the middle and thinner at its edges. | 1. A concave lens is thicker at the edges and thinner in the middle |
| 2. A light beam converges on passing through a convex lens. | 2. A light beam diverges on passing through a concave lens. |
| 3. The convex lens produces a real image that is inverted and is smaller and can be obtained on screen. | 3. A concave lens always forms a virtuall image, the image is magnified and cannot be obtaiined on screen. |
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संबंधित प्रश्न
An illuminated object is placed at a distance of 20 cm from a converging lens of focal length 15 cm. The image obtained on the screen is:
(a) upright and magnified
(b) inverted and magnified
(c) inverted and diminished
(d) upright and diminished
A converging lens is used to produce an image of an object on a screen,object on a screen. What change is needed for the image to be formed nearer to the lens?
(a) increase the focal length of the lens
(b) insert a diverging lens between the lens and the screen
(c) increase the distance of the object from the lens
(d) move the object closer to the lens
If the image formed by a lens is always diminished and erect, what is the nature of the lens?
An object is placed at a distance of 4 cm from a concave lens of focal length 12 cm. Fine the position and nature of the image.
An object 60 cm from a lens gives a virtual image at a distance of 20 cm in front of the lens. What is the focal length of the lens? Is the lens converging or diverging? Give reasons for your answer.
State whether the following statement is true or false:
Short-sightedness can be cured by using a concave lens.
Where will the image be formed if an object is kept in front of a concave lens at a distance equal to its focal length? Draw a ray diagram to illustrate your answer.
The power of a lens is negative. State whether it is convex or concave.
Draw neat diagram to show the
Divergent action of concave lens
The focal length of a lens is negative. In this case, state the kind of lens.
