Question #aaeaa

2 Answers
Feb 10, 2018

Positive power(#D#) of a lens means positive focal length(#f#),i.e lens is converging in nature.

They are related as, #D=100/f# (in cm)

So,the lens has a focal length of #100/1.5 =66.67 cm#

And,remember,lens with positive power is given to a patient of Hypermetropia where the eyeball has smaller dimensions than normal and as a result of this refractive error,image is formed behind the fovea.

So a converging lens is recommended, so that it can converge the light more to make the image fall on fovea within that shortened distance.

Feb 10, 2018

#0.67m# it's converging in nature.

Explanation:

#D=1/f#

#f=1/D#

#=1/1.5#

#=0.67m#

Converging lens always posseses positive power.