Q.Why do thick lenses possess chromatic and spherical aberrations? Suggest remedies for the rectification of these defects.
Ans.Chromatic aberration occurs because lenses have a different refractive index for different wavelengths of light (the dispersion of the lens) and spherical aberration is an optical effect observed in an optical device that occurs due to the increased refraction of light rays when they strike a lens or a reflection of light rays when they strike a mirror near its edge, in comparison with those that strike nearer the centre.
Chromatic aberration was reduced by increasing the focal length of the lens where possible.
Q. Does the chromatic aberration takes plane in mirror?
Ans. In optics, chromatic aberration (chromatic distortion) is a type of distortion in which there is a failure of a lens to focus all colors to the same convergence point. It occurs because lenses have a different refractive index for different wavelengths of light (the dispersion of the lens).But A/c to law of reflection” The angle of incidence is always equal to law of refraction”. So there is no chance of chromatic aberration in mirror