Question

What value of direct current must flow through a resistor to produce the same heating power as an alternating current with a peak value of 3.5 A?

(a) 1.5 A

(b) 2.5 A

(c) 3.5 A

(d) 4.5 A

Answer 1

Correct choice is (b) 2.5 A

To explain: Power in dc circuit = Power in ac circuit     (given)

IDC^2R = IRMS^2R

IDC=IRMS

IRMS=I0/√2 = 3.5/√2 = 2.5 A.

IDC=2.5 A.