KIRCHHOFF’S RULES
Kirchhoff’s Rules
1. The sum of the currents entering any junction in an electric circuit
must equal the sum of the currents leaving that junction:
2. The sum of the potential differences across all elements around
any circuit loop must be zero:
Serway 28.19, p. 897
Determine the current in each branch of the circuit shown in the
figure.
Serway 28.24, p. 897
In the circuit of the figure, determine the current in each resistor
and the voltage across the 200-Ω resistor.
SEATWORK Serway 28.18, p. 897
The ammeter shown in the figure reads 2.00 A. Find I1, I2, and ε.
Answers: I1 = 0.714 A, I2 = 1.29 A, ε = 12.6 V
SEATWORK Serway 28.21, p. 897
The circuit considered in Problem 19 and shown in the figure is
connected for 2.00 min. (a) Find the energy supplied by each
battery. (b) Find the energy delivered to each resistor. (c) Find the
total amount of energy converted from chemical energy in the
battery to internal energy in the circuit resistance.
SEATWORK Serway 28.22, p. 897
(a) Using Kirchhoff ’s rules, find the current in each resistor shown in
the figure and (b) find the potential difference between points c and
f. Which point is at the higher potential?
Answers: I1 = 0.385 mA, I2 = 3.08 mA, I3 = 2.69 mA
∆Vcf = –69.2 V, point c is at higher potential
SEATWORK Serway 28.23, p. 897
If R = 1.00 kΩ and ε = 250 V in the figure, determine the direction
and magnitude of the current in the horizontal wire between a and
e.
SEATWORK Serway 28.25, p. 897
A dead battery is charged by connecting it to the live battery of
another car with jumper cables. Determine the current in the
starter and in the dead battery.