Electric field of a point charge — common mistakes

Be careful with signs! Electric field strength (E) is a vector, so its direction is important. Electric potential (V) is a scalar, but its sign (+ or -) matches the source charge and is crucial for calculating potential differences or total potential from multiple charges. Remember the inverse square for E ($1/r^2$) and inverse for V ($1/r$).

Electric field strength (E) is a vector quantity, representing the force per unit charge. Electric potential (V) is a scalar quantity, representing the work done per unit charge (energy per charge). E tells you the force a charge experiences, while V tells you the potential energy a charge would have at that point.

Electric field strength is derived from Coulomb's Law, which states force is inversely proportional to $r^2$. Since $E = F/q$, E also follows $1/r^2$. Electric potential (V) is derived from the work done, which involves integrating the force over distance. This integration reduces the power of $r$ by one, resulting in V being inversely proportional to $r$ ($V \propto 1/r$).

Yes! Electric potential can be negative if the source charge creating the field is negative. A negative potential means that positive work would be done by the field (or negative work against the field) to bring a positive test charge from infinity to that point.

It states that the net electric field (or potential) at a point due to multiple charges is the sum of the fields (or potentials) from each individual charge. For fields, this is a vector sum, requiring you to consider direction. For potential, it's a simple scalar (algebraic) sum.