Find the current in the circuit which supplies an active power of 600 watts and reactive power of 800 VAR, if the voltage applied is 200 V (RMS value).

The correct answer is option 1):(5 A)

Concept:

P = Active power (or) Real power in  W = V_rms I_rms cos ϕ

Q = Reactive power in VAR = V_rms I_rms sin ϕ

S = Apparent power in VA = V_rms I_rms

S = P + jQ

S = \(\sqrt{P^2+Q^2} \)

ϕ is the phase difference between the voltage and current

RMS current (I_rms) = \( S\over V_{rms}\)

Calculation:

Given

V_rms = 200 V

P = 600 Watts

Q = 800 VAR

S = \(\sqrt{P^2+Q^2} \)

= \( \sqrt{600^2+ 800^2} \)

= 1000

RMS current (Irms) = \( S\over V_{rms}\)

= \(1000 \over 200\)

= 5 A