Question

If $R$ and $L$ are resistance and inductance of a choke coil and $f$ is frequency of current through it, then average power of the choke coil is proportional to

• A. $R$
• B. $\frac{1}{r^2}$
• C. $\frac{1}{L^2}$
• D. All of these

Answer 1

The correct option is A $R$

As $\overrightarrow{P}=V_{rms}{I}_{rms}\cos \varphi =\frac{V_0{I}_0}{2}\cos \varphi$

where, $\cos \varphi =\frac{R}{Z}=\frac{R}{wL}$

or $\overrightarrow{P}=\frac{V_0{I}_0}{2}\times \frac{R}{2\pi fL}$

$\therefore \overrightarrow{P}=$ average power $\propto R$