Circuit Theorems in AC Analysis - Engineering

Q1:

Referring to the given circuit, how much power, in watts, is delivered to the speaker at the determined frequency if VS = 4.5 VRMS?

A 226 mW

B 2.26 mW

C 4.24 mW

D 424 mW

ANS:D - 424 mW

Ieq = Vs/Req.
= 4.5/(12+12)
= 0.1875 A.

P = I^2 Rw.
= (0.1875)^2 (12).
= 422 mW.