Reply To: Midterm Exam Question 8

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Susan BrownSusan Brown

This is a good time to firm up your understanding of current and voltage.

Voltage can exist without current. You can have a potential voltage – for example, across an open switch. The difference in charge exists between the two points, but since the circuit is open, no current can yet flow.

Also, remember that in a series circuit, current is either flowing or it isn’t, throughout the whole circuit. You can’t have current flowing in one portion and not another, or at different rates.

This is where the concept of voltage drop is also helpful. When current flows through a load and that load does work, it will create a voltage difference from one side of the load to the other. We call this “voltage drop.”

So, in Figure 1 of Question 9, we obviously measure some potential voltage (with respect to a neutral point), but is there a voltage drop? What does that tell us?