Advertisements
Advertisements
Question
Name the physical quantity whose unit is dioptre.
Advertisements
Solution
The power of a lens is a physical quantity with dioptre as it's unit.
APPEARS IN
RELATED QUESTIONS
Calculate the focal length of a corrective lens having power +2D.
What is meant by a power of a lens? Define its SI unit.
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 focal length of a convex lens is 25 cm. What is its power?
What is the power of a convex lens lens whose focal length is 80 cm?
The power of a lens is, −2 D. What is its focal length?
The focal length of a lens is +150 mm. What kind of lens is it and what is its power?
Express the power (with sign) of a concave lens of focal length 20 cm.
Name the type of lens whose power is positive.
The image of an object formed by a lens is real, inverted and of the same size as the object. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens ? Draw ray diagram to justify your answer.
How does focal length of a lens change when red light incident on it is replaced by violet light? Give reason for your answer.
A thin converging lens is formed with one surface convex and the other plane. Does the position of image depend on whether the convex surface or the plane surface faces the object?
Which lens has more power a thick lens or a thin 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 above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.
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?
When monochromatic red light is used instead of blue light in a convex lens, its focal length will ______.
In what unit is the power of a lens expressed?
