What ensures that the total current entering a junction equals the total current leaving it in a complex circuit?
**Kirchhoff's loop rule** (energy conservation) states algebraic sum of potential differences around closed loop zero, Σ ε - Σ I R =0, ensures total voltage drop across series resistors equals source emf. Junction rule (charge conservation) Σ I_in = Σ I_out ensures current continuity. Kirchhoff’s junction rule, based on charge conservation, ensures that charge does not accumulate at a junction in steady state, so the sum of currents in equals the sum out. Applying I = n e A v_d, R = ρ l/A, R_t = R₀[1+αΔT], Kirchhoff's ΣI=0, ΣV=0, R_eq series/parallel, V = ε - I r and P = I²R, evaluation yields Charge
Ref: NCERT > Physics Book > Current Electricity > Kirchhoff's Laws and Combination of Resistors