Advertisements
Advertisements
प्रश्न
Complete the diagram to show the formation of the image of the object AB.
(i) Name the Lens LL’.
(ii) Where is the image of the object AB formed?
(iii) State three characteristics of the image.
Advertisements
उत्तर
(i) The lens is a diverging (or concave) lens.
(ii) The image of the objects is A’B’ which is formed between the optical centre and focus of the lens, in front of it.
(iii) The image is (a) virtual, (b) upright, and (c) diminished.
संबंधित प्रश्न
The lens mentioned in 6(b) above is of focal length 25cm. Calculate the power of the lens.
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 power of a lens is, −2 D. What is its focal length?
A convex lens of focal length 25 cm and a concave lens of focal length 10 cm are placed in close contact with one another.
(a) What is the power of this combination?
(b) What is the focal length of this combination?
(c) Is this combination converging or diverging?
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
A double convex lens has two surfaces of equal radii R and refractive index \[m = 1 \cdot 5\]
Focal length : metre : : power of 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 |
The focal length of a concave lens is 20 cm. The focal length of a convex lens is 25 cm. These two are placed in contact with each other. What is the power of the combination? Is it diverging, converging or undeviating in nature?
The focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
