What is the power factor in a series circuit?

[hidemi]

Homework Statement

A series circuit consists of a 15-Ω resistor, a 25-mH inductor, and a 35-μF capacitor. If the frequency is 100 Hz the power factor is:

The answer is 0.45

Relevant Equations

PR / Pavg = Irms^2 * R / Irms^2*Z

I calculated in the following and got the correct answer. However, I wonder whether this way is correct or not. Thanks!

PR / Pavg = Irms^2 * R / Irms^2*Z = 15 /33.36 = 0.45

 

[BvU]

Hi,

and got the correct answer

So how did you get the 33.36 ? From 15/0.45 ? Then the answer is per se correct, but 'the way' is not

And you have me wondering why you type 33.36 and not 33.33

$\$

 

[hidemi]

Hi,

So how did you get the 33.36 ? From 15/0.45 ? Then the answer is per se correct, but 'the way' is not (15^2

And you have me wondering why you type 33.36 and not 33.33

$\$

z=√[15^2 + (100*2π*25*10^-3 - 1/(100*2π*35*10^-6))^2]

Hi,

So how did you get the 33.36 ? From 15/0.45 ? Then the answer is per se correct, but 'the way' is not

And you have me wondering why you type 33.36 and not 33.33

$\$

My detailed calculation is as attached.

 

[Delta2]

Yes the power factor is $\cos\phi=\frac{R}{Z}$.

 

[hidemi]

Yes the power factor is $\cos\phi=\frac{R}{Z}$.

Ok Thank you, I understand.