SAT Subject Physics Practice Question 666: Answer and Explanation
2. When a switch is closed to operate a DC circuit, the electrons that cause the current
A. travel from the negative plate of the battery to the positive plate.
B. travel from the positive plate of the battery to the negative plate.
C. travel from one resistance to the next resistance.
D. travel from the negative plate of the battery to the positive plate inside the battery.
E. travel from one atom in the circuit to the next atom.
Correct Answer: E
The correct answer is (E). The battery that provides the force to push electrons through the circuit causes the electrons to jump from atom to atom, a process that causes the current to flow. The process is similar to water flowing in a hose. Water enters one end of the hose and leaves the other end, but they are not the same water molecules.