In an a.c. circuit the e.m.f. ( ε) and the current (i) at any instant are given respectively by ε = E0sin ω t, i = I 0sin( ω t -φ) The average power in the circuit over one cycle of a.c. is (a) (E₀ I₀)/(2)cos φ (b) E₀ I₀ (c) (E₀ I₀)/(2) (d) (E₀ I₀)/(2)sin φ

Answer: (a). Pavg = ErmsIrmscos φ Erms = (E₀)/(√(2)), Irms = (I₀)/(√(2)) So the answer is (a) (E₀I₀)/(2)cos φ.

In an a.c. circuit the e.m.f. ( ε) and the current (i) at any instant… | NEET 2008 (AIPMT)

Q75NEET 2008 · AIPMTEasy

Power, Power Factor & Wattless Current

In an a.c. circuit the e.m.f. ( $\varepsilon$ ) and the current

(i) at any instant are given respectively by

$\varepsilon$ = E0sin $\omega$ t, $i = I$ 0sin( $\omega$ t $-\phi$ )

The average power in the circuit over one cycle of a.c. is

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Answer: (a)