Question

3. An
lens surface generally decreases in power peripherally in order to correct the aberrations found
in the periphery of the lens.
a) Spherical
b) Aspheric
c) Both a & b
d) None of the above.​

Answer 1

Answer:

Mate your Answer is Here

A) Spherical

Answer 2

Answer:Spherical aberration exacerbates myopia in low light (night myopia). In brighter conditions, the pupil constricts, blocking the more peripheral rays and minimizing the effect of spherical aberration.The simplest method of reducing spherical aberration is to place an aperture, hole or "stop", in front of or after the lens. The aperture blocks out rays that blur the image. The disadvantage is, however, a greatly reduced light throughput of the lens. Spherical aberration is most commonly corrected by use of a mirror with a different shape. Usually, a parabolic mirror is substituted for a spherical mirror. The outer edges of a parabolic mirror have a significantly different shape than that of a spherical mirror.Spherical aberration is present when the outer parts of a lens do not bring light rays into the same focus as the central part. Images formed by the lens at large apertures are therefore unsharp but get sharper at smaller apertures

Explanation: