A number of resistors are connected across points A and B as shown in the figure.What is the equivalent resistance between points A and B?
A)4 Ω
B)6 Ω
C)8 Ω
D)10 Ω
E)12 Ω

Question

A number of resistors are connected across points A and B as shown in the figure.What is the equivalent resistance between points A and B? 
A)4 Ω 
B)6 Ω 
C)8 Ω 
D)10 Ω 
E)12 Ω

Quizplus · Accepted Answer

The first step is to identify which resistors are in series and which are in parallel.

The 2 Ω and 3 Ω resistors are in series, so we can simplify them to a single equivalent resistor:

2 Ω + 3 Ω = 5 Ω

There are now two resistors in parallel: the 5 Ω resistor and the 5 Ω resistor. We can use the formula for resistors in parallel to find the equivalent resistance:

1/Req = 1/5 Ω + 1/5 Ω

1/Req = 2/5 Ω

Req = 5/2 Ω = 2.5 Ω

Finally, the 4 Ω resistor is in series with the 2.5 Ω equivalent resistor, so we can add them together to get the total equivalent resistance:

4 Ω + 2.5 Ω = 6.5 Ω

Therefore, the closest option is C) 8 Ω.

A Number of Resistors Are Connected Across Points a and B