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 2 A in the same resistor, is

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

Answer 1

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

Heat produced by AC=3*heat produced by the DC

Therefore, $i_{rms}^{2}Rt=3\ast i^{2}Rt$

$i_{rms}^2=3\ast 2^2$

$i_{rms}=2\sqrt{3}$=3.46A