Question

Power of a lens is the reciprocal of its _________________________________

5. The SI unit of power of a lens is ___________________________

6. The centre of the reflecting surface of a spherical mirror is a point called the

_______________________.
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Answer 1

Answer:

A dioptre (British spelling) or diopter (American spelling) 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.) It is thus a unit of reciprocal length

Answer 2

Explanation:

1. Power of a lens is the reciprocal of its Focus.

2. The SI unit of power of a lens is Diopter.

3. The centre of the reflecting surface of a spherical mirror is a point called the Pole.