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)

Resistance $R=10\, \Omega$
Peak value of current $I_{0}=2 A$
Rms value of current $I_{ rms }=\frac{I_{0}}{\sqrt{2}}=\frac{2}{\sqrt{2}}=\sqrt{2} A$
Power dissipated $P=I_{r m s}^{2} R$
$\Rightarrow P=(\sqrt{2})^{2} \times 10=20\, W$