Alternating Current: Practice Problem & Solution

Solution Explained:

To solve this problem, we apply the core principles of Alternating Current. Understanding the underlying formula is key to arriving at the correct answer below:

Net reactance is $X = X_L - X_C = 31 - 25 = 6 \Omega$.
Impedance $Z = \sqrt{R^2 + X^2} = \sqrt{8^2 + 6^2} = 10 \Omega$.
Power factor is $\cos\phi = \frac{R}{Z}$.
$\cos\phi = \frac{8}{10} = 0.80$.