PhysicsChapter 5: Electric Potential and Capacitor
Electric Potential Due To A Point Charge
The electric potential at distance `r` from an isolated point charge `Q`, taking zero potential at infinity, is: **V = kQ/r** where:
Definition
The electric potential at distance `r` from an isolated point charge `Q`, taking zero potential at infinity, is: V = kQ/r where: k = 14πε₀
Mathematical form
V = kQ/r** where
k = 1/(4πε
Sign
The electric field of a point charge is: E = kQ/r² Potential is obtained by considering work per unit charge from infinity to the point. The result is: V = kQ/r If: `Q > 0` then: **V > 0 relative to infinity. If: `Q < 0` then: V < 0**
Distance Dependence
Potential decreases as: **1r This is different from electric-field strength: E ∝ 1r²**
Potential Energy Between Two Point Charges
If another charge `q` is placed at distance `r`: **U = qV Therefore: U = kQq/r**
Formula / Key Relation
**V=kQ/r U=kQq/r k≈8.99×10⁹ N m² C⁻²**
Exam preparation
Exam Focus
Quick revision
Revision Zone
Review the key facts, formulas and checks before you move on.Electric Potential Due To A Point Charge
Sticky Notes · Quick Revision
Point charge:
- `V=kQ/r`
- Positive Q → positive V
- Negative Q → negative V
60-second revision
- Potential decreases inversely with distance.
Did you understand this topic?
Your answer is saved with your learning record. It does not mark the topic as mastered.