Advertisements
Advertisements
Questions
Define the power of a lens.
Define the term power of a lens.
Advertisements
Solution 1
Power of a lens is defined as the ability of a lens to bend the rays of light. It is given by the reciprocal of focal length in metre.
Solution 2
The power of a lens is a measure of the deviation produced by it in the path of rays refracted through it.
APPEARS IN
RELATED QUESTIONS
Find the focal length of a lens of power −2.0 D. What type of lens is this?
What is the focal length of a convex lens of focal length 30 cm in contact with a concave lens of focal length 20 cm? Is the system a converging or a diverging lens? Ignore thickness of the lenses.
A doctor has prescribed a corrective lens of power, −1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
On reducing the focal length of a lens, its power ______.
A normal eye is not able to see objects closer than 25 cm because
A symmetric double convex lens in cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4 D, the power a cut-lens will be
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 |
Assertion and reasoning type
- Assertion: Myopia is due to the increase in the converging power of eye lens.
- Reason: Myopia can be corrected with the help of concave lens.
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.
