Question

The power factor of R-L circuit is $\frac{1}{\sqrt{3}}$. If the inductive reactance is $2\Omega$. The value of resistance is

• A. $2\Omega$
• B. $\sqrt{2}\Omega$
• C. $0.5\Omega$
• D. $\frac{1}{\sqrt{2}}\Omega$

Answer 1

Answer: (B)

$\cos \varphi =\frac{1}{\sqrt{3}},\tan \varphi =\frac{\sqrt{2}}{1}\tan \varphi$
$=\frac{X_L}{R}\sqrt{2}=\frac{2}{R}$
$\Rightarrow R=\sqrt{2}\Omega$