Question

The rms value of an alternating current, which when passed through a resistor produces heat three times of that produced by a direct current of 2A in the same resistor, is

• A. 6A
• B. 3A
• C. 2A
• D. 2$\sqrt{3}$A

Answer 1

The correct option is D 2$\sqrt{3}$A

$Qrms=3Q_{DC}$
$i_{rms}^2=3i_{dc}^2$
$i_{rms}=\sqrt{3}2=2\sqrt{3}A$