A real image can be formed on a screen, whereas a virtual image:

The focal length of a plane mirror is:

The primary colors of light are:

The working principle of an optical fiber is based on:

Which mirror is used as a rear-view mirror in vehicles?

Total internal reflection occurs when light travels from a:

The critical angle is the angle of incidence for which the angle of refraction is:

The unit used to measure the power of a lens is:

The human eye lens is:

The color with the longest wavelength in the visible spectrum is:

Myopia occurs when the eyeball is: