Chapter 1, Problem 18P

A voltage source $V_s$ is used to apply two different voltages (12V and 18V) to the single-loop circuit shown in Fig. P1.18. The values of the measured current are shown in Fig. P1.18. The voltage and current satisfy the linear relation $V_s=IR+V$. where R is the resistance in ohms. I is the current in amps, and $V_s$ is the voltage in volts.

(a) Using the data given in Fig. P1.18, and the equation of the line for $V_s$, as a function of 1, and determine the values of R and V. (b) Sketch the graph of $V_s$, as a function of I and dearly indicate the resistance R and voltage V on the graph.