Question

In P (t) equation, if θ=0, then P (t) =?

(a) (VmIm/2)(1+cos⁡ωt)

(b) (VmIm/2)(cos⁡ωt)

(c) (VmIm/2)(cos⁡2ωt)

(d) (VmIm)(1+cos⁡2ωt)

This question was posed to me during an interview.

Query is from Instantaneous Power topic in portion Power and Power Factor of Network Theory

Answer 1

Right option is (d) (VmIm)(1+cos⁡2ωt)

To elaborate: In P (t) equation, if θ=0⁰, then P (t) =(VmIm/2)(1+cos⁡2ωt). The power wave has a frequency twice that of the voltage or current. Here the average value of power is VmIm/2.