Madhya Pradesh Police Exam Model Paper 6

The correct answer is Dioptre.
CONCEPT:

• Power is the ability to bend light and it is equal to the reciprocal of the focal length of the lens/mirror in meters.

Power (P) = 1/f
Where f is the focal length of the lens/mirror.
EXPLANATION:

• The SI unit of the focal length is the meter (m).

So the SI unit of power = 1/(SI unit of focal length) $={\mathit{m}}^{-1}$ = Dioptre (D).
$1{\mathit{m}}^{-1}$ = 1 D

1. Watt is the SI unit of power for energy consumption.
2. The SI unit of the power of a lens is given by Dioptre.
3. Candela is the SI unit for the luminous intensity of an object.
4. Centimetre measures the distance.
5. SI unit of distance is metre.