Chapter 1

Q. 1.P.4

When a resistor R is connected to a current source it consumes a power of 18 W. When the same resistor R is connected to a voltage source whose magnitude is same as the current source, the power absorbed is 4.5 W. The values of current source and R are ____.


Verified Solution

Consider the circuits shown in Fig. (a) for R connected to current source and Fig. (b) for R con-necte to voltage source.

Given that      i_{ S }=V_{ S }


\begin{aligned} i_{ S }^2 R & =18  W \\ \frac{V^2}{R} & =4.5  W \\ R^2 & =\frac{18}{4.5}=\frac{180}{45}=4  \Omega \\ R & =2  \Omega \\ i_{ S }^2 & =\frac{18}{2}=9 \Rightarrow i_{ S }=3  A \end{aligned}