Getting your Trinity Audio player ready...

Hold down the T key for 3 seconds to activate the audio accessibility mode, at which point you can click the K key to pause and resume audio. Useful for the Check Your Understanding and See Answers.

Current - help4

Current refers to the rate at which charge passes a point on a circuit. We picture charges as marching together around the circuit as a group. As such, the current is the same at all locations within a circuit. The direction of current outside the battery pack, by convention, is from the positive terminal to the negative terminal.

There are two similar versions of this question. Here is one of the versions:

Version 1:

The diagram shows a circuit with a 3-cell battery, two light bulbs, and three labeled locations. If 10 units of charge flow past point A in 20 seconds, then …
5 units of charge will flow past point C in 10 seconds.
20 units of charge will flow past point C in 10 seconds.
10 units of charge will flow past point C in 10 seconds.
10 units of charge will flow past point C in 5 seconds.

What is Current?
Current is defined as the amount of charge that passes a point per unit of time. It is a ratio of charge amount to time. Its units are Coulombs per second. (The Coulomb is the metric unit for charge.) Sometimes we refer to a Coulomb per second as an ampere or amp.

In effect, when you are determining the current in a circuit, you begin by selecting any point on the wire. You then take a time period - maybe 10 seconds - and you "count" the number of charges that pass by that point in that time period. Then you divide the amount of charge by the time. The result is the current

It doesn't matter what point you pick when you do this measurement of current. You could pick a point in front of the first bulb or a point after the last bulb. Since the current is the same at every point in the circuit, this method will give you the same value for current regardless of the location.

Try this link to The Physics Classroom Tutorial for more help with the concept of electric current:

Electric Current