# Power problem

Discussion in 'Homework Help' started by metelskiy, Feb 23, 2011.

1. ### metelskiy Thread Starter Member

Oct 22, 2010
66
3
I have 3 different problems:
1. A 0.5H inductor has a resistance of 150 ohms. The current flowing through the inductor is 0.4A at a frequency of 60Hz.What is the real power dissipated by the inductor?
2.A 0.5H inductor has a resistance of 150 ohms. The current flowing through the inductor is 0.4A at a frequency of 60Hz. What is the reactive power in the inductor?
3. A 0.5H inductor has a resistance of 150 ohms. The current flowing through the inductor is 0.4A at a frequency of 60Hz. What is the apparent power in the circuit

So basically in all three problems it has same inductor, same resistance and same current through it.
1. I found real power to be 24W ($V_L=0.4A \cdot 150ohms=60v$ then $Q=60V \cdot 0.4A=24W$ The reason I know its 24W because it was among the multiple choice answers but in my understanding the real power can only be dissipated by a Resistor, how in this problem inductor dissipates 24W of real power?
2. To find reactive power I'm not sure how to find that. By using power triangle, I only know 24W.
3. If i'll find out Real and Reactive powers i should be able to calculate Apparent power.

You must determine X, the imaginary part of the inductor's impedance Z (its reactance). This is defined as jωL. ω is found by $2 \times \pi \times f$. Reactive power is then $Q=I \small _{RMS}^2 \large \times X$