Question 379: Ray Optics

Question

For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behinf the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be

Accepted Answer

P
cornea
= + 40 D
P
e
= + 20 D
Total power of combination = 40 + 20 = 60 D
Focal length of combination = $${1 \over {60}} 	imes 100$$ cm = $${5 \over 3}$$ cm
For minimum converging state of eye lens,
u = -$$\infty $$ v = ? f = $${5 \over 3}$$
From lens formula,
$${1 \over f} = {1 \over v} - {1 \over u}$$
$$ \Rightarrow $$ v = $${5 \over 3}$$ cm
Distance between retina and cornea-eye lens
= $${5 \over 3}$$ cm = 1.67 cm

Answer

1.67 cm

Answer

1.5 cm

Answer

5 cm

Answer

2.5 cm

Ray Optics

For a normal eye, the cornea of eye provides a converging power of 40 D and the least converging power of the eye lens behinf the cornea is 20 D. Using this information, the distance between the retina and the cornea-eye lens can be estimated to be

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