Question

A driving point impedance with poles at ω = 0, ω = ∞ must have excess ___________ term in the numerator polynomial.

(a) s^1+ωn^1

(b) s^1+ωn^2

(c) s^2+ωn^2

(d) s^2+ωn^1

I had been asked this question in final exam.

This intriguing question originated from Frequency Response of Reactive One-Ports topic in portion Elements of Realizability and Synthesis of One-Port Networks of Network Theory

Answer 1

Right option is (c) s^2+ωn^2

Easy explanation: The driving point impedance of the one-port is infinite, and it will not pass either direct current or alternating current of an infinitely high frequency.