Question

in following circuit the resistance of a resistor is R=25 ohm and inductive reactance of an inductor is Xl = 12 ohm what is the value of power factor of the circuit if supply AC voltage is 230 V at 50 Hz

Answer 1

Answer:

Power factor (cos phi) = 0.9

Explanation:

We know that the formula for power factor is:

$cos\phi = \frac{R}{Z}$

And Z ( Impedance ) = $\sqrt{R^2 + (X_L - X_C)^2}$

So,

$cos\phi = \frac{R}{\sqrt{R^2 + (X_L - X_C)^2}}$

If we put in all the values we get

$cos\phi = \frac{25}{\sqrt{625 + (12 + 0)^2}}$

$X_C = 0$  since there is no capacitor mentioned in the circuit.

So after solving it we get

$cos\phi = \frac{25}{\sqrt{769}}$

$cos\phi = \frac{25}{27.7}$

$cos\phi = 0.9$

A good thing to remember is that the power factor always lies between 0 and 1.