Two resistors 4 Ω and 6 Ω in series are connected to 24 V. Current and voltage across the 4 Ω resistor?

• A. I = 1.2 A; V4Ω = 4.8 V
• B. I = 3.0 A; V4Ω = 12.0 V
• C. I = 4.8 A; V4Ω = 19.2 V
• D. I = 2.4 A; V4Ω = 9.6 V

Answer: (D)

In a series circuit, the same current flows through every component, and the voltage divides in proportion to resistance. Add the resistors: 4 Ω + 6 Ω = 10 Ω. With 24 V across the series, the current is I = 24 V / 10 Ω = 2.4 A. The voltage across the 4 Ω resistor is V4Ω = I × R = 2.4 A × 4 Ω = 9.6 V. The remaining voltage drops on the 6 Ω resistor (2.4 A × 6 Ω = 14.4 V), and together they sum to 24 V. So the current is 2.4 A and the voltage across the 4 Ω resistor is 9.6 V.