An EM wave making arbitrary alpha, beta and gamma angle with x,y and z axes respectively is divided into its components along the three axes? What does it even mean? If the components along the three axes are the components of the oscillating electric fields at different time, then these components cannot be considered separate EM waves because the direction of the changing electric fields along the axes would be like an oscillating spring along respective axis, not longitudinal as needed.
It was assumed that the arbitrarily directed EM wave makes a standing wave. I don’t understand how an EM wave falling not perpendicular to a surface might reverse back along the same direction it hit the surface? (The wave is in a cube with each side length ‘a’.)
Let’s say the wave makes a standing wave somehow. In the proof, different planes were imagined through the nodes and perpendicular to the direction of the wave so the oscillating electric field is parallel with the planes. Why was it important? And how equations 1-13 were written?
- In the next page, why the three electric field components had to have their values zero at ‘a’ distance away? What good will it do? How can it guarantee that in this way the original (initial) wave would have its node upon hitting the wall of the cube if the electric field components had their values zero at ‘a’ distance away?