In the dispersion of white light by a prism,which color of light undergoes the maximum deviation?

How does an eye manage to see objects in dim light and bright light?

$(a)$ If a person wears a lens of power $-6\, D$ for distant vision and for correcting his near vision he needs a lens of $+2\, D$. Determine the focal length of the lenses in both the cases.
$(b)$ Give reasons for the following natural phenomena:
$(i)$ Stars twinkle.
$(ii)$ Planets do not twinkle.
$(iii)$ Stars appear raised in the sky.

Pigments are mixed by the $......$ method to produce various colors.

Which lens is used to correct the defect of myopia (nearsightedness)?

Define dispersion of white light.