College Physics 10th Edition by Raymond Serway,Chris Vuille

Exercise 39

The circuit in Figure P18.50a consists of three resistors and one battery with no internal resistance. (a) Find the current in the 5.00- resistor. (b) Find the power delivered to the 5.00- resistor. (c) In each of the circuits in Figures P18.50b, P18.50c, and P18.50d, an additional 15.0-V battery has been inserted into the circuit. Which diagram or diagrams represent a circuit that requires the use of Kirchhoff's rules to find the currents Explain why. (d) In which of these three new circuits is the smallest amount of power delivered to the 10.0-V resistor (You need not calculate the power in each circuit if you explain your answer.)