Question

A sinusoidal A.C. current flows through a resistor of resistance $10\Omega$. If the peak current is $2$ A flowing through the resistor then the power dissipated in __________W.

• A. $30$
• B. $20$
• C. $10$
• D. $40$

Answer 1

Answer: (B)

$20$

Resistance $R=10\Omega$
Peak value of current $I_o=2A$
Rms value of current $I_{rms}=\frac{I_o}{\sqrt{2}}=\frac{2}{\sqrt{2}}=\sqrt{2}A$
Power dissipated $P=I_{rms}^{2}R$
$⟹P=(\sqrt{2}{)}^2\times 10=20W$
Correct answer is option B.