Question

An alternating e.m.f. of 200V and 50 cycles is connected to a circuit of resistance 3.142 $\Omega$ and inductance 0.01H. The lag in time between the e.m.f. and the current is :

• A. 1.5 ms
• B. 2.5 ms
• C. 3.5ms
• D. 0.5 ms

Answer 1

The correct option is B 2.5 ms

SInce load angle is

$tan\left(\theta \right)=\frac{\omega L}{R}=\frac{2\pi fL}{R}$

$tan\theta =\frac{2\pi \times 50\times 0.01}{3.142}=1$

$\theta =\omega t_{lag}=\frac{\pi }{4}$

$t_{lag}=2.5m\sec .$