The kirchhoff's first law is based on-

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 to 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 the 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 the 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:

• According to Kirchhoff’s current law (KCL), the algebraic sum of the electric currents meeting at a common point is zero. I.e. the sum of currents entering a node is equal to the sum of currents leaving the node.
• It is based on the conservation of charge.
• So, Kirchhoff's first law is the law of conservation of charge.
• Hence option 3 is correct.