Question

If a farsighted person has a near point that is 0.600 m from the eye, what is the focal length f2 of the contact lenses that the person would need to be able to read a book held at 0.350 m from the person's eyes? Express your answer in meters. View Available Hint(s) f2 = nothing

Answer 1

0.84 cm

Step-by-step explanation:

u = Object distance = 0.35 cm

v = Image distance = -0.6 cm (near point is considered as image distance and negative due to sign convention)

f = Focal length

From lens equation

`(1)/(f_2)=(1)/(u)+(1)/(v)\\\Rightarrow (1)/(f_2)=(1)/(0.35)+(1)/(-0.6)\\\Rightarrow (1)/(f_2)=(25)/(21)\\\Rightarrow f_2=(21)/(25)=0.84\ cm`

Focal length of the lens is 0.84 cm