Question

a person needs a lens of power of -5.5diopters for correcting his distant vision. For correcting is near vision he needs a lens of power + 1.5 diopter what is the focal length of the lens required for correcting distant vision

Answer 1

given power of lens for corecting distant vision is -5.5D

relation between power and focal length is P=1/f (or)  f=1/P

f=1/5.5    f=0.1818m

(or) f=18.18cm

So the focal length required to correct the distant vision is 18.18cm.