Circuit Comparison Compare and contrast the voltages and the currents in series and parallel circuits. 60. Total Current A parallel circuit has four branch currents:120 mA. 250 mA, 380 mA, and 2.1 A. How much current passes through the power source? 61. Total Current A series circuit has four resistors. The current through one resistor is 810 mA What current passes through the power source? 62. Circuits You connect a switch in series with a 75-W bulb to a 120-V power source. a. What is the potential difference across the switch when it is closed (turned on)? b. What is the potential difference across the switch when it is opened (turned off)? 63. Loop Rule Compare Kirchhoff's loop rule to walking around in a loop on the side of a hill 64. Junction Rule Explain how Kirchhoff's junction rule relates to the law of conservation of charge. 65. Critical Thinking The circuit in picture has four identical resistors in parallel. Suppose that a wire is added to conned points A and B. Answer the following questions. and explain your reasoning. a. What is the current through the wire? b. What happens to the cement through each resistor? c. What happens to the current through the battery? d. What happens to the potential difference across each resistor ?