Question

Kirchhoff's current and voltage law are respectively based on the conservation of

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

Hint:

To easily remember this, think of the alphabet and definitions: Current is the flow of Charge (KCL $\rightarrow$ Charge), and Voltage is electric potential Energy per unit charge (KVL $\rightarrow$ Energy).

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks us to identify the fundamental physical conservation laws that form the theoretical basis for Kirchhoff's Current Law (KCL) and Kirchhoff's Voltage Law (KVL).

Step 2: Key Formula or Approach:
* Kirchhoff's Current Law (KCL): States that the algebraic sum of currents meeting at any electrical node or junction is zero ($\sum I = 0$). This is a direct consequence of the conservation of electric charge. * Kirchhoff's Voltage Law (KVL): States that the algebraic sum of potential differences around any closed circuit loop is zero ($\sum V = 0$). This is a direct consequence of the conservation of energy.

Step 3: Detailed Explanation:
According to the principle of conservation of charge, electric charge cannot accumulate or vanish at an ideal circuit junction. Therefore, the total charge entering a node per unit time must perfectly equal the total charge leaving that node per unit time. This validates that KCL is based on the conservation of charge. According to the principle of conservation of energy, when an electric charge moves around a complete closed loop and returns to its initial position, the net work done on it by conservative electrostatic forces must be exactly zero. This means the total energy gained from voltage sources must equal the total energy dissipated across resistive elements, validating that KVL is based on the conservation of energy.

Step 4: Final Answer:
The conservation principles are charge and energy, respectively, which corresponds to option (C).