What is meant by power of a lens? What does its sign indicate? State its SI unit.
Answers
Answer:
The power of a lens is defined as the reciprocal of its focal length in meters, or D = 1/f
where D is the power in diopters and f is the focal length in meters
The ability of converging or diverging of the light rays passing through the lens is known as power of the lens. ~ The +ve sign of the power indicates that the lens is a converging lens or convex lens, whereas the negative sign of the power indicates that the lens is concave or diverging lens.
Si unit-
A dioptre or diopter is a unit of measurement of the optical power of a lens or curved mirror, which is equal to the reciprocal of the focal length measured in metres. (1 dioptre = 1 m−1.)
Explanation:
I hope it will help you
Answer:
The deviation of the incident light rays produced by a lens on refraction through it, is measure of its power.
If lens deviates a ray towards its centre, power is positive. If it deviates the ray away from its centre, then Power is negative. Power of covex lens is positive and that of concave lens is negative.
Unit of Power if Dioptre (symbol D)