Question

An alternating emf given by equation $E=300sin\left[\right(100\pi \left)t\right]$ $volt$ is applied to a resistance $100ohms$. The rms current through the circuit is (in $amperes$):

• A. $\frac{3}{\sqrt{2}}$
• B. $\frac{9}{\sqrt{2}}$
• C. $3$
• D. $\frac{6}{\sqrt{2}}$

Answer 1

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

Alternating emf equation $E=300$ $sin\left(100\pi t\right)$

$\therefore$ Peak emf $E_o=300$ $volts$

The rms emf $E_{rms}=\frac{E_o}{\sqrt{2}}=\frac{300}{\sqrt{2}}$ $volts$

Value of resistance $R=100\Omega$

$\therefore$ Value of rms current $I_{rms}=\frac{E_{rms}}{R}=\frac{300}{\sqrt{2}\times 100}=\frac{3}{\sqrt{2}}$ $A$