Question

what is Kirchoff's first law

Answer 1

Kirchoff got himself a huge name in physics by simply applying two principles of physics to electrical circuits. This is the first:

At any junction in a circuit, the sum of the currents arriving at the junction = the sum of the currents leaving the junction.

In other words - charge is conserved. If this doesn't happen you'd either get a massive build-up of electrons at a junction in a circuit or you would be creating charge from nowhere! That's not going to happen.

Answer 2

Some relationships do exist between voltages and currents under various branches of an electrical circuit. These relationships are identified by the laws of which are known as Kirchhoff’s laws, derived by Guatov Robert Kirchhoff. These laws help in calculating the electrical resistance of a complex network or impedance in case of AC and the current flow in different streams of the network.Is it enough?