Four 1000 Ω resistors in parallel have a total resistance of?

Four 1000 Ω resistors in parallel have a total resistance of?

• A. 250 Ω
• B. 400 Ω
• C. 500 Ω
• D. 1000 Ω

Answer: (A)

In parallel, current has multiple paths, so the total resistance is lower than any one resistor. To find the total resistance, add the reciprocals of each resistor and take the reciprocal of that sum: 1/R_eq = 1/R1 + 1/R2 + 1/R3 + 1/R4. With four identical resistors of 1000 ohms, 1/R_eq = 1/1000 + 1/1000 + 1/1000 + 1/1000 = 4/1000 = 1/250, so R_eq = 250 ohms. For equal resistors in parallel, you can also think of it as dividing the single-resistor value by the number of resistors: 1000 divided by 4 equals 250. This matches the idea that adding parallel paths lowers the total resistance.

In parallel, current has multiple paths, so the total resistance is lower than any one resistor. To find the total resistance, add the reciprocals of each resistor and take the reciprocal of that sum: 1/R_eq = 1/R1 + 1/R2 + 1/R3 + 1/R4. With four identical resistors of 1000 ohms, 1/R_eq = 1/1000 + 1/1000 + 1/1000 + 1/1000 = 4/1000 = 1/250, so R_eq = 250 ohms. For equal resistors in parallel, you can also think of it as dividing the single-resistor value by the number of resistors: 1000 divided by 4 equals 250. This matches the idea that adding parallel paths lowers the total resistance.