Question

All eyeglass lenses have chromatic aberration. This is usually expressed as dioptric spread. For a typical +6.0 D lens, the focusing power for red light is +5.90 D,the power for green light is +6.00 D, and the power for blue light is +6.10 D. This gives a dioptric spread of 0.20 diopter. Suppose a myopic person is observing a distant object through this lens, and the green light of the image is in perfect focus. Assume a distance s′ = 1.7000 cm.

> How far in front of or behind the retina is the point of sharp focus for red light? Express your answer with the appropriate units. Enter positive value if the point of sharp focus is behind the retina and negative value if the point of sharp focus is in front of the retina.

Δs′red = ___ (value) ___ (units)

> How far in front of or behind the retina is the point of sharp focus for blue light? Express your answer with the appropriate units. Enter positive value if the point of sharp focus is behind the retina and negative value if the point of sharp focus is in front of the retina.

Δs′blue = ___ (value) ___ (units)

Answer 1