Advertisements
Advertisements
Question
Differentiate convex lens and concave lens.
Advertisements
Solution
| Convex Lens | Concave Lens |
| 1. The lens which is thicker at the centre than at the edges. | 1. The lens is thinner at the centre than at the edges. |
| 2. Abeam of light passing through it, is converged to a point. | 2. A beam of light passing through it is diverged or spread out. |
| 3. It is called a converging lens. | 3. It is called a diverging lens. |
APPEARS IN
RELATED QUESTIONS
A student did an experiment with a convex lens. He put an object at different distances 25 cm, 30 cm, 40 cm, 60 cm and 120 cm from the lens. In each case he measured the distance of the image from the lens. His results were 100 cm, 24 cm, 60 cm, 30 cm and 40 cm, respectively. Unfortunately his results are written in wrong order.
Rewrite the image distances in the correct order.
What kind of lens can form:
an erect magnified image?
A parallel oblique beam of light falls on a convex lens. Draw a diagram to show the refraction of light through the lens.
To find the image distance for varying object distances in case of a convex lens of focal length 15 cm, a student obtains on a screen a sharp image of a bright object by placing it at 20 cm distance from the lens. After that he gradually moves the object away from the lens and each time focuses the image on the screen.
(a) In which direction-towards or away from the lens does he move the screen to focus the object?
(b) How does the size of image change?
(c) Approximately at what distance does he obtain the image of magnification –1?
(d) How does the intensity of image change as the object moves farther and farther away from the lens?
While determining the focal length of a convex lens, you try to focus the image of a distant object formed by the lens on the screen. The image formed on the screen, as compared to the object, should be
(A) erect and highly diminished
(B) erect and enlarged
(C) inverted and enlarged
(D) inverted and highly diminished
State the position of object, position of image, nature of image when: Convex lens is used as objective lens of photographic camera.
In sunglasses, both of its surfaces are curved, yet their behaviour is neither like a convex lens nor like a concave lens. State the reason.
Why do we say that the ‘2F’ and ‘F’ points of a convex lens can be regarded as a sort of ‘turning points’ as far as the nature of the image formed by it is concerned?
Find the odd one out and give its explanation.
Distinguish between:
Concave lens and Convex lens
