Explanation:

- Option 1: Energy

- The electron-volt (eV) is indeed a unit of energy.

- It's defined as the amount of kinetic energy gained or lost by an electron when it is accelerated through a potential difference of one volt.

- Extremely useful in the fields of particle physics and quantum mechanics.

- Correct Answer

- Option 2: Power

- Power is the rate of doing work or the rate of energy transfer.

- It's commonly measured in watts (W), not electron-volts.

- Option 3: Current

- Current is the flow of electric charge over time.

- It's measured in amperes (A), not in electron-volts.

- Option 4: Potential Difference

- Potential difference is the difference in electric potential between two points.

- It's measured in volts (V), not electron-volts.