Question

The Kirchhoff's first law $(\sum i=0)$ and second law $(\sum iR=\sum E)$,
where the symbols have their usual meanings, are respectively based on :

• A. conservation of charge, conservation of momentum
• B. conservation of energy, conservation of charge
• C. conservation of momentum, conservation of charge
• D. conservation of charge, conservation of energy

Answer 1

Answer: (D)

KirchhofPs 1st law or KCL states that the algebaric sum of current meeting at any junction is equal to zero. In other words we can say that " the sum of all the currents directed towards a junction in a circuit is equal to the sum of all the currents directed away from that junction." Thus, no charge has been accumulated at any junction i.e., charge is conserved, and hence, we can say that $KCL$ $(\sum i=0)$ is based on conservation of charge.
Kirchhoffs Ilnd law or $KVL$ states that algebraic sum of changes in potential around any closed resistor loop must be zero. In other words "around any closed loop, voltage drops are equal to voltage rises". No energy is gained or lost in circulating a charge around a loop, thus, we can say that $KVL$ is based on conservat ion of energy.