Thirteen resistors are connected across points A and B as shown in the figure.If all the resistors are accurate to 2 significant figures,what is the equivalent resistance between points A and B?
A) 4.0 Ω
B) 6.0 Ω
C) 8.0 Ω
D) 10 Ω
E) 12 Ω

Question

Thirteen resistors are connected across points A and B as shown in the figure.If all the resistors are accurate to 2 significant figures,what is the equivalent resistance between points A and B? 
A) 4.0 Ω 
B) 6.0 Ω 
C) 8.0 Ω 
D) 10 Ω 
E) 12 Ω

Quizplus · Accepted Answer

We can simplify the circuit by combining resistors in series and parallel. Starting from the leftmost side, we can combine the 6 Ω and the 4 Ω resistors in series to get a total of 10 Ω. Then, combining the 10 Ω and the 5 Ω resistors in parallel, we get a total resistance of 3.333 Ω. Continuing to the right, we can combine the 2.5 Ω and the 5 Ω resistors in series to get 7.5 Ω, and combining the 7.5 Ω and the 10 Ω resistors in parallel, we get a resistance of 4.286 Ω. Finally, combining the 3.333 Ω and the 4.286 Ω resistances in series, we get an equivalent resistance of approximately 7.619 Ω. Rounding this value to 2 significant figures gives us 8.0 Ω, which is the closest answer choice.

Thirteen Resistors Are Connected Across Points a and B as Shown