How is electric potential difference between two points defined?

The correct option is Work done per unit charge.

Explanation

Electric potential difference is a scalar quantity that measures the energy difference per unit charge between two points in an electric field. It determines the direction of the flow of positive charge.

• Work done per unit charge is Correct: The electric potential difference between two points is defined as the amount of work done required to move a unit positive charge from one point to the other against the electrostatic force. Mathematically, it is expressed as \( V = \frac{W}{Q} \), where \( V \) is the potential difference, \( W \) is the work done, and \( Q \) is the charge.
• Charge flow per unit time is Incorrect: The flow of electric charge per unit time is the definition of electric current (\( I = \frac{Q}{t} \)).
• Power per unit charge is Incorrect: Power is defined as the rate at which work is done or energy is transferred (\( P = \frac{W}{t} \)). It is not defined per unit charge in this context.
• Current per unit length is Incorrect: Current per unit length is not a standard definition for potential difference.

Key Takeaway:

Electric potential difference is physically defined as work done per unit charge. Its SI unit is the Volt (V), where 1 Volt equals 1 Joule per Coulomb (1 V = 1 J/C).