Question

A $12\Omega$ resistor and a $0.21H$ inductor are connected in series to an a.c source operating at $20V$, $50cycle/second$. The phase angle between current and source voltage is

• A. ${30}^o$
• B. ${40}^o$
• C. ${80}^o$
• D. ${90}^o$

Answer 1

The correct option is C ${80}^o$

The phase angle is given by
$\tan \varphi =\frac{\omega L}{R}=\frac{2\pi \times 50\times 0.21}{12}=5.5$
$\varphi ={\tan }^{-1}5.5={80}^o$