The battery drives current through R3 into a node where the circuit splits
into two parallel branches, R1 and R2, before recombining. Kirchhoff's Current
Law says the currents into that node sum to the currents out; Kirchhoff's
Voltage Law says the voltage drop around any loop sums to zero.
KCL: ΣI_in = ΣI_out at every node
KVL: ΣV = 0 around every closed loop
I = V / R (Ohm's law, per resistor)
R_parallel = (R1·R2)/(R1+R2), R_total = R3 + R_parallel
- Source voltage — the EMF driving current around the whole circuit.
- R1 / R2 — the two parallel branch resistances; current splits inversely to resistance.
- R3 — the series resistance the full current passes through before the split.
- Glowing particles move faster along lower-resistance paths — exactly as more current flows there.