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In an a.c. circuit the instantaneous emf and current are e=100 sin 30t and i=20 sin (30t-π/4). In one cycle, the average power consumed and the wattless current are, respectively

Asked in JEE Main 2019 (paper/shift not legible in scan) · Wattless current

Answer: (2) (1000)/(√2), 10

Step-by-step solution

P_avg=1/2 V₀ I₀ cos φ=1/2(100)(20)cos 45°=(1000)/(√2) W.

Wattless current =Iᵣₘₛ sin φ=(20)/(√2)sin 45°=10 A.

Why the other options are wrong

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