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An AC Source of 200V rms supplies an active power of 600W and reactive power of 800VAR. The rms current drawn from the source is

(a) 10A

(b) 5A

(c) 3.75A

(d) 2.5A

Answer is ( b )

Concept

Explanation: $V_{s} = 200V (rms)$

$P = 600W , Q = 800VAR$

$P = V_{s}I_{s}cos\phi = 600$

$\therefore I_{s}cos\phi = 600/200 = 3 $...Eqn(1)

$Q = V_{s}I_{s}sin\phi = 800$

$\therefore I_{s}sin\phi = 800/200 = 4 $...Eqn(2)

$\therefore$ From Eqn(1) and (2) $I_{s}^{2}(sin^{2}\phi + cos^{2}\phi)$ = 9 +16 = 25