Question

Which of the following is not true?

(a) A conductor carrying alternating current radiates

(b) A transmission line must not radiate energy

(c) Antennas are transmission lines which are made to radiate energy

(d) A parallel wire transmission, when left open, does not radiate

The question was asked in homework.

This interesting question is from Antenna Fundamentals in section Antennas and Wave Propagation of Avionics

Answer 1

The correct answer is (d) A parallel wire transmission, when left open, does not radiate

For explanation I would say: If a parallel-wire transmission line is left open, the electric and magnetic fields escape from the end of the line and radiate into space. This radiation, however, is inefficient and unsuitable for reliable transmission or reception.