Question

The power factor of an ac circuit having resistance (R) and inductance (L) connected in series and an angular velocity $\omega$ is

• A. $R / \omega L$
• B. $R / \left( R ^ { 2 } + \omega ^ { 2 } L ^ { 2 } \right) ^ { 1 / 2 }$
• C. $\omega L / R$
• D. $R / \left( R ^ { 2 } - \omega ^ { 2 } L ^ { 2 } \right) ^ { 1 / 2 }$

Answer 1

Answer: (B)

$R / \left( R ^ { 2 } + \omega ^ { 2 } L ^ { 2 } \right) ^ { 1 / 2 }$

Answer 2

$\cos \phi = \frac { R } { Z } = \frac { R } { \left( R ^ { 2 } + \omega L ^ { 2 } \right) ^ { 1 / 2 } }$