If three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28-volt circuit, how much current will flow through the 3-ohm resistor?

If three resistors of 3 ohms, 5 ohms, and 22 ohms are connected in series in a 28-volt circuit, how much current will flow through the 3-ohm resistor?

• A. 1.20 ampere
• B. 0.50 ampere
• C. 0.93 ampere
• D. 2.0 ampere

Answer: (C)

In a series circuit, the same current flows through every component. To find that current, first add the resistances: 3 + 5 + 22 = 30 ohms. The total current is then I = V / R_total = 28 V / 30 Ω ≈ 0.933 A, which rounds to 0.93 A. So the current through the 3-ohm resistor is also about 0.93 A. For context, the voltage across each resistor would be V = I × R, so the 3-ohm drop is about 0.93 × 3 ≈ 2.8 V, the 5-ohm drop ≈ 4.7 V, and the 22-ohm drop ≈ 20.5 V, adding up to 28 V. The other numbers don't fit because changing the current would require a different total resistance or voltage; in a series circuit the current is shared identically by all components.

In a series circuit, the same current flows through every component. To find that current, first add the resistances: 3 + 5 + 22 = 30 ohms. The total current is then I = V / R_total = 28 V / 30 Ω ≈ 0.933 A, which rounds to 0.93 A. So the current through the 3-ohm resistor is also about 0.93 A.

For context, the voltage across each resistor would be V = I × R, so the 3-ohm drop is about 0.93 × 3 ≈ 2.8 V, the 5-ohm drop ≈ 4.7 V, and the 22-ohm drop ≈ 20.5 V, adding up to 28 V. The other numbers don't fit because changing the current would require a different total resistance or voltage; in a series circuit the current is shared identically by all components.