Question

b) Find the power delivered to an element at t = 3 ms if the current entering its positive terminal is i = 5cos60πt A and the voltage is

(i) v = 3i

(ii) v = 3di/dt         

Answer 1

$P=iv,$

a)

$v=15\cos60\pi t,$

$P=75\cos^260\pi t,$

$P(3)=75~W,$

b)

$v=-900\pi \sin 60\pi t,$

$P=-2250\pi \sin 120\pi t,$

$P(3)=0.$