🔍 Key Concepts

• Ohm’s Law (V = I × R) and how voltage, current, and resistance relate • How voltage divides in a series circuit vs how it behaves in a parallel circuit • Using the total supply voltage and known resistor values to find the drop across one resistor

💭 Think About

• Is R1 in series with the other resistors, in parallel, or part of a mixed network? How does that affect its share of the voltage? • Can you first find the total current in the circuit from the source voltage and total resistance, then use that to find the voltage across R1? • If there is more than one resistor in series with the supply, how is the total voltage divided according to their resistances?

✅ Before You Answer

• Make sure you correctly identify where R1 is located in the circuit in Figure 3B1 • Confirm you are using the correct total resistance when computing circuit current • Before choosing an answer, check that the sum of all series voltage drops equals the source voltage (within rounding).