Analog and electronic circuits

Which correctly states Kirchhoff's current law (first law)?

  1. AThe sum of currents flowing into a node equals the sum of currents flowing out
  2. BThe sum of voltages around a closed loop is zero
  3. CThe current through a resistor is proportional to the voltage
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Answer: A. The sum of currents flowing into a node equals the sum of currents flowing out

Kirchhoff's current law states that the sum of currents entering a node (junction) equals the sum leaving it, expressing conservation of charge. The sum of voltages around a closed loop being zero is the voltage law (second law), and current proportional to voltage is Ohm's law.

  • A. Correct. Currents in and out of a node are equal.
  • B. This is Kirchhoff's voltage law (second law).
  • C. This is Ohm's law.
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