What is the total resistance of a series circuit containing 4 Ω and 8 Ω resistors?

What is the total resistance of a series circuit containing 4 Ω and 8 Ω resistors?

• A. 4 Ω
• B. 8 Ω
• C. 12 Ω
• D. 2 Ω

Answer: (C)

In a series circuit, the total resistance is the sum of the individual resistances. The current has a single path through each resistor, so their resistive effects add up. For 4 Ω and 8 Ω in sequence, you simply add them: 4 + 8 = 12 Ω. So the total opposition to current is 12 ohms, which is larger than either resistor alone—typical of a series connection. The other numbers would only apply if you had a different arrangement or a single resistor in the path, which isn’t the case here, so 12 Ω is the correct total.

In a series circuit, the total resistance is the sum of the individual resistances. The current has a single path through each resistor, so their resistive effects add up.

For 4 Ω and 8 Ω in sequence, you simply add them: 4 + 8 = 12 Ω. So the total opposition to current is 12 ohms, which is larger than either resistor alone—typical of a series connection.

The other numbers would only apply if you had a different arrangement or a single resistor in the path, which isn’t the case here, so 12 Ω is the correct total.