Which part of the eye is responsible for changing the focal length of the eye lens by adjusting its thickness?

What are the colors obtained by mixing primary colors called?

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

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

To correct astigmatism,we use a cylindrical lens.

Draw ray diagrams each showing $(i)$ myopic eye and $(ii)$ hypermetropic eye.