🔍 Key Concepts
• Recognize from figure B whether R1, R2, and R3 are in series or parallel once the switch is closed
• Use the equivalent resistance of parallel resistors formula to find the total resistance seen by the 12 V source
• Apply Ohm’s Law: ( I = \frac{V}{R_{total}} ) to find the total current from the battery
💭 Think About
• From the drawing, do all three resistors share the same two connection points, or are they end‑to‑end? What does that tell you about the type of circuit?
• Write the equation for ( \frac{1}{R_{total}} ) using the given values for R1, R2, and R3, and simplify it carefully.
• Once you have ( R_{total} ), plug it into Ohm’s Law with 12 V and see which answer choice matches that current value.
✅ Before You Answer
• Confirm that in figure B, R1, R2, and R3 are indeed in parallel, not series.
• Double‑check your calculation of equivalent resistance; a parallel combination’s total resistance should be less than the smallest single resistor.
• Verify your units: resistance in ohms, voltage in volts, and current in amperes, and be sure the current you compute matches exactly one of the choices.