What is the total resistance in a DC series circuit with R1 = 15 kohms, R2 = 25 kohms, and R3 = 47 kohms?

To determine the total resistance in a DC series circuit, you simply add the resistance values of each component together. In this case, you have three resistances: R1, R2, and R3.

The total resistance ( R_{total} ) can be calculated using the formula:

[ R_{total} = R1 + R2 + R3 ]

Substituting the values:

[ R_{total} = 15 , \text{kohms} + 25 , \text{kohms} + 47 , \text{kohms} ] [ R_{total} = 15 + 25 + 47 ] [ R_{total} = 87 , \text{kohms} ]

This result shows that when resistors are connected in series, the total resistance is the sum of the individual resistances. This principle applies because, in a series circuit, the current flowing through each resistor is the same, and hence, the resistances effectively add up to limit the total current.

Considering the answer choices, the total resistance of 87 kohms aligns precisely with option C, confirming it as the correct answer.