Question

How does Kirchoff’s current law in circuit theory relates to the physical law of charge conservation?

Answer 1

Kirchoff's current law in circuit theory does relate to the physical law of charge conservation.

The physical law of charge states the in a closed system charge can neither be created nor be destroyed it can just be transferred.

Kirchoff's current law states that, sum of all currents entering the junction = sum of all currents leaving the junction.

Current is simply the flow of electric charge. As charge can neither be created nor destroyed at the junction, charge entering the junction should be same as the charge leaving the junction and therefore the current entering the junction should be same as the current leaving it.