Find the magnitude of instantaneous poynting vector at

Question

The electric fields received at point P from two identical, coherent wave sources are E₁(t)=Ecos(ωt+Φ) and E₂(t)=Ecosωt

Part A
Find the resultant wave.

Part B

What is the amplitude of this resultant wave?

Part C

Use the result of part (a) to show that at an interference maximum, the amplitude of the resultant wave is in phase with the original waves E₁(t) and E₂(t).

Part D

Use the result of part (a) to show that near an interference minimum, the resultant wave is approximately 14 cycle out of phase with either of the original waves.

Part E

Find the magnitude of instantaneous Poynting vector at point P.

Part F

Finf the expression for the magnitude of time-averagedPoynting vector.