A battery is defined as which of the following?

• A. A single electrochemical cell
• B. A device for measuring current
• C. An electrolytic cell in series
• D. A set of voltaic cells connected in a series, so the negative electrode of one cell is connected to the positive electrode of the next

Answer: (D)

A battery is a device that stores and delivers electrical energy by combining multiple electrochemical cells. In a battery, these cells are connected in series so that the negative terminal of one cell is linked to the positive terminal of the next, causing their voltages to add and producing a higher overall emf than a single cell. This setup distinguishes a battery from a single electrochemical cell and from other electrical devices.

A single electrochemical cell can generate voltage, but the term battery typically refers to a set of voltaic (galvanic) cells arranged together. The other options describe different things: a device for measuring current isn’t a battery, an electrolytic cell operates with external energy to drive non-spontaneous reactions, and the essence of a battery in standard chemistry definitions is the series arrangement of multiple cells.