*I need help with part b* following problem will allow you to combine the knowle

Question

*I need help with part b*

following problem will allow you to combine the knowledge of the thin lens equation with the relation between the geometry of the lens and it's focal length. Consider the human eye to be composed of a thin, plano-convex, lens (similar to the one shown in your lab write up and in earlier problems of this pre-lab) of uniform index of refraction n = 1.45, submerged into fluid of n = 1, with the light-receptive cells a distance 21.3 mm from the lens. The eye can "focus" on different distances by changing the radius of curvature of its lens.

a) Find the radius of curvature for this lens when you are looking at very distant objects. (all incident light rays must hit the light-receptive cells at the same point) 9.585 (correct) equation used: R = f(n-1)

b) Find the radius of curvature for this lens when you are looking at an object a distance of 51.5 mm from your eye's lens. (all incident light rays must still hit the light-receptive cells at the same distance as before)

Explanation / Answer

given that

refractive index n1=1.45

refractive index n2=1

image distance V=21.3 mm=0.0213 m

this problem belongs to refraction at spherical surfaces

hence gassion surface

n2/v - n1/u = n1-n2/R

(a) ans

the radius of curvature of for this lens

1/0.0213 - 1.45/0 = 1.45-1/R

46.95 - 0 =0.45/R

R=0.45/46.95 = 9.585 mm

[b] ans

here the object distance u=51.5 mm =0.0515 m

the image distance V=21.3 mm = 0.0213 m

the radius of curvature for lenses

n2/v - n1/u = n1 - n2 /R

1/0.0515 - /0.0213 = 1.45 -1 /R

19.41+68.08= 0.45/R

radius of curvature =0.45/87.5=5.143 mm

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