Question

Differentiate between a wavefront and a ray.

Hint:

A wavefront shows the shape of the propagating wave, while a ray shows its direction.

Answer 1

Difference Between Wavefront and Ray 

A wavefront is the locus of all points that are in the same phase of vibration.
A ray is an imaginary line that represents the direction of wave propagation. 
It is always perpendicular to the direction of wave propagation. 
It is always perpendicular to the wavefront. 
Examples: Plane wavefront, spherical wavefront. 
Used to represent light beams in geometrical optics.