Kirchhoff's **voltage (loop) law** in any closed loop of an electrical network states:
- $\sum P = 0$
- $\sum IR + \sum \varepsilon = 0$
- $\sum I = 0$
- $V = IR$ only
Show answer and solution
Correct answer: B. $\sum IR + \sum \varepsilon = 0$
Around any closed loop, $\sum IR + \sum \varepsilon = 0$.
This is **conservation of energy** — the net energy gained per unit charge in one full loop is zero.