What is the phase difference between two points on a wavefront?

Assertion: Phase difference between any two points on a wavefront is 180^@ Reason:Phase depends on distance of the two points from the source.

What is the potential difference between two points in the electric field? Name its SI unit.

Two points are located at a distance of 10 m and 15 m from the source of oscillation .theperiod of oscillation is 0.05 sec and the velocity of the wave is 300 m s^(-1) .What is the phase difference between the oscillation of two points?

What is meant by saying that the potential difference between two points is 1 V?

Differentiate between a ray and a wavefront.

What is the phase difference between voltage across the inductance and a capacitor in an a.c. circuit?