Question

Write the one power of concave lens of the focal length 5m

Answer 1

F=-5m

Now

P=1/F

P= -1/5

P= - .02D

Hope thse would helps u

Answer 2

$\huge{Focal \: length = - 5m (as\: it \:is \:a \:concave \:lens)}$

$\huge{\therefore power, P = \frac{1}{f}}$

$\huge={\frac{-1}{5}}$

$\huge={-0.2 D}$

$\huge\boxed{Answer = -0.2D}$