As demonstrated on page 964, we used the principle of charge conservation to derive the formula for total resistance in a parallel circuit. The steps were the following:
 Apply Ohm’s law (in the form I = V/R) to each resistor individually.
 Add the currents through each resistor to get the total current.
 Apply Ohm’s law (in the form R = V/I) to get the total resistance.
Which of the abovelisted steps is a statement of Kirchhoff’s first law?
 1 only
 2 only
 1 and 3 only
 1, 2, and 3
