In a resistance model, RT denotes the total resistance.

• A. Total resistance in the circuit
• B. Only the resistance of the first component
• C. The rate of current flow
• D. The voltage drop across the load

Answer: (A)

RT is the total (equivalent) resistance of the entire circuit as seen from the source. It condenses all the resistors, whether in series or parallel, into a single value that determines how hard it is for current to flow through the whole network. Using Ohm’s law, the total current is Itotal = Vtotal / RT, so RT sets how much current the source can push for a given voltage. It’s not the rate of current itself (that’s Itotal), not the voltage drop across the load (that depends on the load’s own resistance and the current), and not simply the resistance of a single component. RT represents the combined resistance of the circuit.