Question

Name a device that helps maintain potential difference across a conductor.

Answer 1

Hint : Electricity is the flow of charge and charge flows from higher potential to lower potential. If charge does not flow, no electricity is conducted. As the electricity flows, the potential difference also decreases.

Complete step by step answer
A conductor is any material that conducts electricity, that is, it allows the flow of electrons through itself. These allow electrons to flow through them which allow passage of electric current. Metals are examples of good conductors.
Electric Potential is defined as the work done to move one unit of charge from one point to another in an electric field.
Potential Difference, as the name suggests, is the difference of electrical potential between two points in an electric field. It is measured in volts (V).
When the two ends of a wire have a potential difference then electric current flows through it.
Ohm's Law states that the current I through a conductor is directly proportional to the potential difference across the two points.
One device that helps maintain potential difference across a conductor is a battery or a cell.
A battery, on the other hand, stores energy chemically. One side of the battery has an excess of electrons and is thus negatively charged while the other side has a deficit of electrons and is positively charged. The excess electrons move towards the positive electrode, thus creating a voltage. Once the electrons are balanced on both sides, the battery no longer has potential difference and it is dead.
A cell supplies energy to do work upon the charge, wherein it is moved from one point (the negative terminal) to another point (the positive terminal). The charge flows from the high potential terminal, through the wires to the low potential terminal. The movement of charge through an electric circuit is analogous to the movement of heat from high temperature to low temperature.
Potential difference is basically the potential energy difference per unit of charge. So a cell is the device that maintains the potential difference across a conductor.

Note
Potential difference is commonly called voltage. Other devices that can maintain potential difference across conductors include various other sources of electricity.