The potential difference $V$ and the current $i$ flowing through an instrument in an ac circuit of frequency $f$ are given by $V = 5\cos{\omega t}\ volts$ and $I = 2\sin{\omega t}amperes$ (where $\omega = 2\pi f$). The power dissipated in the instrument is

Question

Dr. Abubacker · Accepted Answer

(a) $V = 5\cos{\omega t} = 5\sin\left( \omega t + \frac{\pi}{2} ight)$ and $i = 2\sin{\omega t}$
Power $= V_{r.m.s.} 	imes i_{r.m.s.} 	imes \cos{\phi = 0}$
[Since $\phi = \frac{\pi}{2},$ therefore $\cos\phi = \cos\frac{\pi}{2} = 0$]

Q. The potential difference $V$ and the current $i$ flowing through an instrument in an ac circuit of frequency $f$ are given by $V = 5\cos{\omega t}\ volts$ and $I = 2\sin{\omega t}amperes$ (where $\omega = 2\pi f$). The power dissipated in the instrument is

Explanation

Reviewed by Dr. Abubacker

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