Question

2. Prove that no longitudinal electromagnetic wave exists in a vacuum. (10pt, no partial scores)
Note:
1. You must start from the Maxwell equation included in the textbook. If you use the form of the Maxwell equation not in the textbook, your score will be 0.
2. Hint: If you prove this from sinusoidal plane wave, you can generalize that it is valid for general wave as well (you can use it without proof.)

Answer 1