Question

When the terminals of an EMF device are connected, and the charges on the terminals are drawn out through the wires, why does its potential difference between terminals not come down eventually?

• A. The potential difference does come down.
• B. There is some internal mechanism in the device keeping the potential difference between the terminals constant.
• C. The potential increases because it’s an emf device.
• D. The electric field is responsible for keeping the EMF constant

Answer 1

The correct option is B There is some internal mechanism in the device keeping the potential difference between the terminals constant.

We use an EMF device not just to provide a potential difference to a conductor but to “maintain” a potential difference across it. The internal mechanism of the battery is responsible for doing so.