Question

In an a-c circuit the reactance of coil is $\sqrt{3}$ times its resistance. The phase difference between the voltage across the coil to the current through coil is

• A. $\frac{\pi }{4}$
• B. $\frac{\pi }{6}$
• C. $\frac{\pi }{2}$
• D. $\frac{\pi }{3}$

Answer 1

The correct option is D $\frac{\pi }{3}$

$cos\Phi =\frac{R}{Z}=\frac{R}{[\sqrt{R^2+(\sqrt{3}R{)}^2}{]}^{1/2}}$
$\Rightarrow cos\Phi =\frac{R}{2R}=\frac{1}{2}$
$\Rightarrow \Phi ={60}^{\circ }$ (or) $\frac{\pi }{3}$