Question: what equation is used to find equivalent resistance?
Answer: The equivalent resistance of a 4-Ω and 12-Ω resistor placed in parallel can be determined using the usual formula for equivalent resistance of parallel branches: 1 / Req = 1 / R1 + 1 / R2 + 1 / R3 ... Now the Ohm's law equation (ΔV = I • R) can be used to determine the total current in the circuit.