Question

One dioptre is the power of a lens of focal length 1 m.

Answer 1

what do you want to ask clear it in the question

Answer 2

$1dioptre \: is \: power \: of \: lens \: \\ whose \: focal \: length \: is \: 1cm \: \\ \\ 1d= \frac{1}{1m}$

$hope \: my \: answer \: helps \: you$