Question

What is the radiation resistance of the antenna radiating at 5kW and having maximum current 2A?

(a) 25kΩ

(b) 2.5kΩ

(c) 0.25kΩ

(d) 2.5Ω

The question was posed to me during an internship interview.

The doubt is from Radiation Resistance in chapter Antenna Parameters of Antennas

Answer 1

Right option is (b) 2.5kΩ

Explanation: \(I_{rms}=\frac{I_m}{\sqrt{2}}=\frac{2}{\sqrt{2}}=\sqrt{2}\)

Power radiated \(P_{rad}=I_{rms}^2 R_{rad}\)

⇨ \(R_{rad}=\frac{P_{rad}}{I_{rms}^2} = \frac{5K}{2}=2.5k\Omega\)