National League for Nursing (NLN PAX) Practice Exam

What is the equivalent resistance of three 3-ohm resistors in series?

1. 3 ohms.

2. 6 ohms.

3. 9 ohms.

4. 12 ohms.

The correct answer is: 9 ohms.

To determine the equivalent resistance of resistors connected in series, you simply add their resistances together. In this case, there are three resistors, each with a resistance of 3 ohms. You would perform the calculation as follows: 3 ohms + 3 ohms + 3 ohms = 9 ohms. Thus, the equivalent resistance of these three 3-ohm resistors in series is 9 ohms. This concept is essential in circuit analysis, as it illustrates how the total resistance increases with the addition of more resistors in series. When resistors are in series, the total resistive effect is cumulative, leading to a larger equivalent resistance than any of the individual resistors.