Gas Fitter Practice Test

What is the combined resistance of two 10 ohm resistors placed in parallel?

1. 5 ohms

2. 10 ohms

3. 20 ohms

4. 30 ohms

The correct answer is: 5 ohms

To determine the combined resistance of two resistors in parallel, you can use the formula for parallel resistors, which states that the reciprocal of the total resistance (R_total) is equal to the sum of the reciprocals of each individual resistance. For two resistors of equal resistance (R1 and R2, both being 10 ohms in this case), the formula can be simplified as follows: 1. Calculate the reciprocal of each resistance: - For each 10-ohm resistor: 1/R1 = 1/10 and 1/R2 = 1/10. 2. Add the reciprocals together: - 1/R_total = 1/10 + 1/10 = 2/10. 3. Invert the result to find R_total: - R_total = 10/2 = 5 ohms. Thus, when two 10-ohm resistors are connected in parallel, their combined resistance is indeed 5 ohms. This demonstrates that combining resistors in parallel reduces the total resistance, as opposed to connecting them in series where the resistances would simply add up. This principle is crucial for understanding how electrical circuits behave, especially when managing load distributions in various applications