Question

The runs value of $AC$ which when passed through a resistor produced heat, which is twice that produced by a steady current of $1.414A$ in the same resistor is:

• A. $2A$
• B. $3.46A$
• C. $2.818A$
• D. $1.732A$
• E. $1A$

Answer 1

The correct option is A $2A$

It is given that the amount of heat produced by AC current is twice of amount of heat produced by DC current.
$I=1.414$A
$\therefore I_{rms}^2\cdot R=2\times I^{2}R$
$I_{rms}^2=2\times (1.414{)}^2=2\times 2$
$\Rightarrow I_{rms}=2A$.