Q107 / 120 · VITEEE 2010 · Physics
Using an AC voltmeter the potential difference in the electrical line in a house is read to be $234 \mathrm{~V}$. If line frequency is known to be 50 cycles/s, the equation for the line voltage is
- A$\quad V=165 \sin (100 \pi t)$
- Correct answerB$\quad V=331 \sin (100 \pi t)$
- C$\quad V=220 \sin (100 \pi t)$
- D$V=440 \sin (100 \pi \mathrm{t})$
Solution
$E=E_{0} \sin \omega t$
Voltmeter read rms value $\therefore E_{0}=\sqrt{2} \times 234 \mathrm{~V}=331 \mathrm{~V}$
and $\omega t=2 \pi n t=2 \pi \times 50 \times t=100 \pi t$ Thus, the equation of the line voltage $E=331 \sin (100 \pi t)$
Hence, the correct answer is option: 'B'.