Define wavefront of light .

What is the geometrical shape of wavefront of light emerging out of a convex lens when a point source is placed at its focus ?

Define refraction of light and explain the relation between refractive index of material and velocity of light.

A wavefront is

Define dispersion of light.

Define: Sap

Define Spectrum of light.

Define wavefront, wavenormal and a ray of light. What are the different types of wavefronts? How are they produced ?

Answer the following questions Define total internal reflection of light.

Define pleura.

Define Growth.