Electric potential is the amount of electric potential energy per unit charge at a given point in an electric field. It is a measure of the work required to move a unit positive charge from an arbitrary reference point to a specific point in an electric field.
Va and Vb are simply two different points in an electric field where we can measure the electric potential. The value of Va may be different from Vb, as the electric potential depends on the distance from the reference point and the strength of the electric field.
The electric potential at a point is calculated by taking the product of the electric field strength at that point and the distance from the reference point. It is also affected by the charge of the particles creating the electric field and the medium in which the field exists.
No, electric potential and electric potential energy are not the same. Electric potential is a measure of the potential energy per unit charge, while electric potential energy is the total amount of potential energy possessed by a charged particle in an electric field.
Yes, electric potential can be negative. This occurs when the reference point used to calculate the electric potential is chosen to be at a higher potential than the point being measured. In this case, the electric potential is negative, indicating that work must be done to move a unit positive charge from the reference point to the measured point.