Kirchhoff's Laws and Conservation Principles

Steps:

• Kirchhoff's first law (KCL) requires the sum of currents at a junction to be zero.
• This enforces conservation of charge, preventing accumulation at the junction.
• Kirchhoff's second law (KVL) requires the sum of voltages around a loop to be zero.
• This enforces conservation of energy, as the work done by the electric field is path-independent.

Why B is correct:

• The first law conserves charge (via current balance), and the second conserves energy (via voltage balance), directly matching the pair in B.

Why the others are wrong:

• A: Names the laws, not the conserved quantities.
• C: Reverses the standard order (first: charge, second: energy).
• D: Momentum conservation does not apply to Kirchhoff's electrical circuit rules.

Final answer: B