Question

A lens has a power of \[+2\,D\]. Its focal length is:

Options

• \[0.5\,m\]

• \[0.2\,m\]

• \[5\,m\]

• \[2\,m\]

Answer 1

Since \[P = \frac{1}{f}\], the focal length is \[f = \frac{1}{P} = \frac{1}{2} = 0.5\,m\]. The positive power confirms that the lens is converging.