3. In a sinusoidal-ac circuit, the current is I=I0sin(ωt +θ) . What is the rms(root-mean-square) current ?
(A) I0 /π
(B) I0 /1.414
(C) I0 /0.707
(D)πI0 
(E) 2πI0

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統計： A(0), B(14), C(1), D(0), E(0) #2241907