What phenomenon is called: a) spherical aberration; b) chromatic aberration?

The rays, after passing through the litas, cross its main optical axis not at one point, but at different ones. The further from the main optical axis the incident beam is located, the closer to the lens this point will be. This phenomenon is called spherical aberration. Due to dispersion, lens focal lengths are different for different light rays. This phenomenon is called chromatic aberration.

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