The formation of an image by a lens is due to which optical phenomenon?

The magnification of a real image formed by a concave mirror is always ...

Define the following terms:
$(i)$ Angle of incidence
$(ii)$ Angle of reflection
$(iii)$ Plane of incidence

What is the distance between the principal focus and the center of curvature of a spherical mirror?

Refractive index of diamond with respect to glass is $1.6$ and absolute refractive index of glass is $1.5$. Find out the absolute refractive index of diamond.

The refractive indices of turpentine oil,kerosene,and alcohol are $1.47, 1.44$,and $1.36$ respectively. Based on this information,complete the following ray diagrams to show the path of a ray of light through each medium. (Give a reason for your answer.)