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Violagirl

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## Homework Statement

A) Under optimum conditions, the smallest black dot that can be seen subtends an angle of 2.3 x 10

^{-6}rad. If a dot is viewed at a distant of 0.25 m, the near point of a normal adult, what is the smallest diameter it can have and still be seen? B) The maximum resolution is obtained when the image falls on the fovea centralis. At 10

^{°}away from this region, the acuity is 10 times poorer. What is the minimum size spot that can be seen at that angle under these conditions?

## Homework Equations

P

_{f}= 1/x

_{f}+ 1/D

P

_{f}= person's far point, 1/x

_{f}= distance a person sees an object, D = image distance

P

_{n}= 1/x

_{n}+ 1/D

P

_{n}person's near point, 1/x

_{n}- distance a person sees an object, D = image distance

A = P

_{n}- P

_{f}

A = power of accommodation

sin θ = 1.22 (λ/d)-power of acuity equation

λ = wavelength, d = diameter

## The Attempt at a Solution

I've puzzled over this problem. I'm not sure what the relevant equation would be unless I'm missing one. Any help is appreciated.