Question

An AC source is 120 V-60 Hz The value of voltage after $\frac{1}{720}s$ from start will be

• A. 20.2 V
• B. 42.4 V
• C. 84.8 V
• D. 106.8 V

Answer 1

Answer: (C)

84.8 V

$\omega =2\pi f=120\pi$

$V_{rms}=120V$

$V_o=\sqrt{2}{V}_{rms}$

$V=V_o\times sin\omega T=120\sqrt{2}sin120\pi \frac{1}{720}=60\sqrt{2}$

$V=84.8V$