An alternating voltage $V = 140 \sin 100 πt$ is connected across a pure resistor of resistance 40 Ω. What is the rms current through the resistor? (Take $\sqrt{2} = 1.4$)
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 2.5 A
The formula for the rms value is -
$I_{rms}=\frac{V_{rms}}{R}$
and,
$V_{rms}=\frac{V_0}{\sqrt{2}}=\frac{140}{\sqrt{2}}=100V$
$⇒I_{rms}=\frac{V_{rms}}{R}=\frac{100}{40}=2.5A$