Which one of the following law is based on the principle of conservation of electric charge?

CONCEPT:

There are two types of Kirchoff’s Laws:

• Kirchoff’s first law: This law is also known as junction rule or current law (KCL). According to it the algebraic sum of currents meeting at a junction is zero i.e. Σ i = 0.

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• In a circuit, at any junction, the sum of the currents entering the junction must be equal the sum of the currents leaving the junction i.e., i1 + i3 = i2 + i4
  • This law is simply a statement of “conservation of charge” as if current reaching a junction is not equal to the current leaving the junction, the charge will not be conserved.
• Kirchoff’s second law: This law is also known as loop rule or voltage law (KVL) and according to it “the algebraic sum of the changes in potential in a complete traversal of a mesh (closed-loop) is zero”, i.e. Σ V = 0.
  • This law represents “conservation of energy” as if the sum of potential changes around a closed loop is not zero, unlimited energy could be gained by repeatedly carrying a charge around a loop.

EXPLANATION:

1. Kirchhoff’s Current Law (KCL) is based on the conservation of charge. So option 1 is correct.
2. Kirchhoff’s Voltage Law (KVL) is based on the conservation of energy.
3. Ohm's law gives the relation between electric current and potential difference.
4. Coulomb's law gives the force between two charges separated by some distance.