Question

The peak value of an alternating e.m.f. E given by $E=E_0\cos \omega t$ is 10 volt and frequency is 50 Hz. At time $t=\left(1/600\right)$ sec, the instantaneous value of e.m.f. is

• A. $10$ volt
• B. $5\sqrt{3}$ volt
• C. $5$ volt
• D. $1$ volt

Answer 1

Answer: (B)

$5\sqrt{3}$ volt

$E=E_{0}cos\omega t=10cos50\times 2\pi \times t$
$=E(t=\frac{1}{600}s)=10cos\frac{100\pi }{600}$
$=10cos\frac{\pi }{6}=5\sqrt{3}$ Volt