Question

a person needs a lens of power -4 D for correction his vision.
a) what kind of defect in vision is she suffering from?
b) what are the causes of this dffect of vision?
c) what is the focal length of the corrective lens ?

Answer 1

I hope this will help you

Answer 2

a,)she is suffering from myopia is defect

b) he can't see long objects clearly


c)now focal length is given by

P=1/F(m)
f=1/P

f = 1\-4
f = -0.25