Question

What is meant by the power of lens? Define its SI unit.

Answer 1

1. Power $\left(P\right)$of a lens is defined as the reciprocal of its focal length$\left(f\right)$.
2. Mathematically it is given as $P=\frac{1}{f}$, where $f$ is the focal length in metre.
3. The SI unit of power of a lens is$dioptre$.