FIGURE 21-7
-Three 2.0-Ω resistors are connected across the sides of an equilateral triangle ABC as shown in Figure 21-7. What is the equivalent resistance between any two points, AB, BC, or AC, of this circuit?
A) 2.0 Ω
B) 6.0 Ω
C) 4.3 Ω
D) 3.3 Ω
E) 1.3 Ω

Question

FIGURE 21-7 
-Three 2.0-Ω resistors are connected across the sides of an equilateral triangle ABC as shown in Figure 21-7. What is the equivalent resistance between any two points, AB, BC, or AC, of this circuit?
A) 2.0 Ω 
B) 6.0 Ω 
C) 4.3 Ω 
D) 3.3 Ω 
E) 1.3 Ω

Quizplus · Accepted Answer

The resistors form a delta (Δ) configuration. The equivalent resistance between any two points in a delta configuration of equal resistors is given by R_eq = R/3, where R is the resistance of each resistor. Here, R = 2.0 Ω, so R_eq = 2.0 Ω / 3 = 0.67 Ω. However, the correct calculation involves using the formula for two resistors in parallel (R_parallel = R/2) and adding the third resistor in series, resulting in R_eq = 1.3 Ω.

FIGURE 21-7 -Three 2.0-Ω Resistors Are Connected Across the Sides of an Sides