Q. A generator produces a voltage that is given by $V = 240\sin{120\ t}$, where $t$ is in seconds. The frequency and $r.m.s.$ voltage are
A) 60 $Hz$ and 240 V
B) 19 $Hz$ and 120 V
C) 19 $Hz$ and 170 V
D) 754 $Hz$ and 70 V
Explanation
(c) $v = \frac{\omega}{2\pi} = \frac{120 \times 7}{2 \times 22} = 19\ Hz$
$V_{r.m.s} = \frac{240}{\sqrt{2}} = 120\sqrt{2} = 170\ V$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.