What is Ray optics or geometrical optics?

What is meant by optical isomerism.

Ray optics is based on:

What is the optical phenomena involved in a rainbow?

What is nature of light? Wave optics and particle nature of light are used to explain which phenomena of light respectively?

Which phenomena can be satisfactorily explained using ray optics? State the assumptions on which ray optics is based.

Answer the following questions Explain the terms optically rarer medium and optically denser medium with examples.

The ray of light travelling from an optically denser medium to optically rarer medium bends

Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

When a monochromatic ray of light travels from an optically denser medium to optically rarer medium then critical angle is the angle of incidence for which angle of refreaction is