Suppose a pair of reading glasses found on the rack in a pha

Suppose a pair of reading glasses found on the rack in a pharmacy has a power of 1.8 D.

Part (a) What is the focal length f, in centimeters?

Here,

power of lens , P = 1.8 D

let the focal length is f

focal length = 100/P cm

focal length = 100/1.80 cm

focal length = 55.6 cm

the focal length of the lens is 55.6 cm