Question

Answer the question fully and you must explain using principles and definitions of biology, environmental science, and physics as appropriate. please write so i can read and explain each part

1. Consider a farsighted person whose range of vision is from 125 cm to very far from the eye. a) What type of lens and what focal length is needed for eyeglasses to correct the vision? b) Draw a ray diagram and locate the image for the lens in part (a) with the object at 30 cm from the lens. c) What type of lens and what focal length is needed for contact lens to correct the vision? d) Suppose the focal length for contact lens were used to make the eyeglasses as a mistake, what is the closest object the person could see with these wrong eyeglasses?

Answer 1

Farsightedness is also known as hypermetropia. a person with this deffect can only see the distant object not the nearby object. Here image is forme far behind the retina.

A) This deffect can be corrected using a convex lense

Given that the near poin of vision is 125 cm

let v be the image distance , u be the object distance and f be the focal length

then v= -125 cm ( by sighn convention)

u = -25 cm (assume that the near poin of normal eye is 25 cm)

then we know that the formula 1/f= 1/v-1/u

that is 1/f =( 1/-125) -(1/ -25)

= 0.032cm

that is f= 0.032 cm is needed to correct the vision

power is p=1/f=31.25 D

so convex lense of 31.25 diopter is needed to correct this deffect

B) the above image