Question

Define one dioptre of power of lens.

Answer 1

In this question we have been asked to define what is one dioptre of power for a lens. Therefore, to answer this question, we shall briefly discuss what is one dioptre and where it is useful. We shall also discuss the formula for dioptre. We know that the dioptre is the unit of measurement of power of a lens or a curved mirror.

Complete step by step answer:
The dioptre is the unit of measurement of power of a lens or a curved mirror. So, basically the dioptre is the SI unit of optical power of the lens. The diameter of a lens or a curved mirror depends on the radius of curvature. More radius of curvature means a thicker lens. This means that the magnification of the lens and its dioptre number will be higher.
The dioptre is usually given as the reciprocal of focal length in metres. Therefore, it is a reciprocal unit of length. It means that when an optometrist gives the prescription for lens in dioptres, he is actually stating the focal length of the lens required to balance the eye defect and provide a good sight after using the lens or spectacles of prescribed power.

Note:
The dioptre filters work as magnifying glass for the lens. The dioptre filter shifts the focus distance. Therefore, sometimes we are able to capture the macro shots without using the macro lens. These filters can be used to increase the magnification of a lens therefore, capturing the magnified image of small objects. In humans the total optical power of the relaxed eye is almost 60 dioptres.