Question

Define Kirchhoff’s first and second law.

Hint:

Kirchhoff’s laws are fundamental tools for analyzing electrical circuits, based on the conservation of charge and energy.

Answer 1

Kirchhoff's First Law (Junction Rule):
Kirchhoff's first law states that the total current entering a junction (or node) is equal to the total current leaving the junction. This is a consequence of the conservation of charge. Mathematically, it can be expressed as: \[ \sum I_{\text{in}} = \sum I_{\text{out}} \] This means that the algebraic sum of all currents at any junction is zero.
Kirchhoff's Second Law (Loop Rule):
Kirchhoff's second law states that the sum of the potential differences (voltage) across all elements around any closed loop or circuit is always equal to zero. This is a consequence of the conservation of energy. Mathematically, it is expressed as: \[ \sum V = 0 \] This means that the sum of the electromotive forces (emfs) and the potential drops (voltage) around a closed loop is zero.
Step 3: Conclusion.
Kirchhoff's laws are essential for solving complex circuits involving multiple components.