Question

When an L–R combination is connected in series with 12V – 50 Hz supply, a current of 0.5A flows through the combination. The current differs in phase from applied voltage by $\frac{\pi }{3}$ rad. Then resistance is

• A. $24\Omega$
• B. $12\Omega$
• C. $6\Omega$
• D. $3\Omega$

Answer 1

The correct option is B $12\Omega$

$Z=\frac{V}{I}=\frac{12}{0.5}=24\Omega$
$Cos60=\frac{R}{Z}$
$R=\frac{Z}{2}=\frac{24}{2}=12\Omega$