Three 300 ohm resistors are wired parallel. What is the total resistance?

Three 300 ohm resistors are wired parallel. What is the total resistance?

• A. 900 ohms
• B. 300 ohms
• C. 150 ohms
• D. 100 ohms

Answer: (D)

In a parallel circuit, the total resistance drops because the current has multiple paths to flow through. The combined resistance is found by adding the reciprocals of each resistor: 1/R_total = 1/R1 + 1/R2 + 1/R3. With all three resistors at 300 ohms, this becomes 1/R_total = 1/300 + 1/300 + 1/300 = 3/300 = 1/100. Taking the reciprocal gives R_total = 100 ohms. For identical resistors in parallel, you can also think of it as dividing the resistance by the number of resistors: 300/3 = 100.

In a parallel circuit, the total resistance drops because the current has multiple paths to flow through. The combined resistance is found by adding the reciprocals of each resistor: 1/R_total = 1/R1 + 1/R2 + 1/R3. With all three resistors at 300 ohms, this becomes 1/R_total = 1/300 + 1/300 + 1/300 = 3/300 = 1/100. Taking the reciprocal gives R_total = 100 ohms. For identical resistors in parallel, you can also think of it as dividing the resistance by the number of resistors: 300/3 = 100.