In a series circuit, how is the total resistance determined?

In a series circuit, how is the total resistance determined?

• A. It is the inverse of the sum of the reciprocals of the individual resistances
• B. It is the product of the individual resistances
• C. It is the sum of the individual resistances
• D. It is the largest individual resistance

Answer: (C)

In a series circuit, resistances add directly to determine the total. The same current flows through every resistor, so the voltage across the entire chain is the sum of the individual drops: V_total = I(R1 + R2 + …). Using Ohm’s law, R_total = V_total / I = R1 + R2 + …. So the total resistance is simply the sum of all the individual resistances. This differs from other arrangements: the reciprocal-sum formula is for parallel configurations, not series. The product of resistances isn’t the general rule for series, and the total isn’t determined by the largest resistor alone—each resistor contributes to the total through a straightforward addition. For example, 4 Ω, 6 Ω, and 10 Ω in series give a total of 20 Ω.

In a series circuit, resistances add directly to determine the total. The same current flows through every resistor, so the voltage across the entire chain is the sum of the individual drops: V_total = I(R1 + R2 + …). Using Ohm’s law, R_total = V_total / I = R1 + R2 + …. So the total resistance is simply the sum of all the individual resistances.

This differs from other arrangements: the reciprocal-sum formula is for parallel configurations, not series. The product of resistances isn’t the general rule for series, and the total isn’t determined by the largest resistor alone—each resistor contributes to the total through a straightforward addition. For example, 4 Ω, 6 Ω, and 10 Ω in series give a total of 20 Ω.