What is the complementary color of red?

Which colour of white light suffers $(i)$ least deviation and $(ii)$ maximum deviation when a beam of white light passes through a glass prism?

Name the two phenomena involved in the formation of a rainbow.

$(a)$ Explain with the help of a labelled diagram how a combination of two prisms can be used so that incident white light emerges out of the second prism as white light.
$(b)$ Name the scientist who first performed this activity.
$(c)$ Explain the term spectrum in brief.

Draw a ray diagram showing the refraction of light through a glass prism and mark the following:
$(a)$ Incident ray
$(b)$ Emergent ray
$(c)$ Refracted ray
$(d)$ Angle of incidence
$(e)$ Angle of deviation
$(f)$ Angle of emergence

The longest and the shortest wavelengths (in $\mu m$) for red and violet light are respectively: