Question

Power radiated by half-wave dipole with maximum current amplitude 10A is ______

(a) 3.65kΩ

(b) 3.650Ω

(c) 0.365kΩ

(d) 36.50Ω

I got this question by my school principal while I was bunking the class.

My question comes from Radiation Resistance topic in chapter Antenna Parameters of Antennas

Answer 1

The correct answer is (a) 3.65kΩ

To elaborate: For a half-wave dipole the radiation resistance is 73Ω.

 \(I_{rms}=\frac{I_m}{\sqrt{2}}=\frac{10}{\sqrt{2}}=5\sqrt{2}\)

Power radiated Prad=Irms^2 Rrad=(5√2)^2×73=3650Ω=3.65kΩ