Dioptre is the SI unit of :
size of the lens.
curvature of the lens.
power of the lens.
magnification produced by a lens.
Answer is Wrong!
Answer is Right!
This question was previously asked in
UPSC CISF-AC-EXE – 2022
Optical power (P) of a lens is defined as the reciprocal of its focal length (f) when the focal length is measured in metres.
P = 1 / f (where f is in metres)
If the focal length f is in metres, the unit of power P is m⁻¹, which is defined as the dioptre (D).
For example, a lens with a focal length of +0.5 metres has a power of P = 1 / 0.5 m = +2 D.
A lens with a focal length of -0.25 metres has a power of P = 1 / -0.25 m = -4 D.
– Optical power is the reciprocal of the focal length measured in metres.