Key Concepts
- Electric Charge: A fundamental property of matter that can be positive or negative.
- Quantization of charge: Charge can exist only in integral multiples of the elementary charge (e).
- Conservation of charge: The total electric charge in an isolated system remains constant.
- Coulomb's Law: The force between two point charges is directly proportional to the product of their magnitudes and inversely proportional to
the square of the distance between them. - Formula: F = k|q1q2|/r^2
- k = 1/(4πε₀) is the Coulomb constant.
- Electric Field: The region around a charge where it exerts an electrostatic force on another charge.
- Electric Field Intensity (E): The force per unit charge at a point in an electric field.
- Formula: E = F/q
- Electric Field Intensity (E): The force per unit charge at a point in an electric field.
- Electric Field Lines: Imaginary lines that represent the direction and strength of the electric field.
- Properties:
- Start on positive charges and end on negative charges.
- Never intersect.
- Closer together where the field is stronger.
- Properties:
- Electric Potential: The work done per unit charge in bringing a test charge from infinity to a point in the electric field.
- Electric Potential Energy (U): The potential energy of a charge due to its position in an electric field.
- Electric Potential Difference (Voltage): The difference in electric potential between two points.
- Capacitance: The ability of a conductor to store charge.
- Capacitance of a Parallel Plate Capacitor: C = ε₀A/d
- Energy stored in a capacitor: U = (1/2)CV^2
Important Formulas
- Force between two charges: F = k|q1q2|/r^2
- Electric field intensity: E = F/q
- Electric potential: V = W/q
- Electric potential energy: U = qV
- Capacitance: C = Q/V
- Energy stored in a capacitor: U = (1/2)CV^2
Key Points
- The direction of the electric field is the direction of the force on a positive test charge.
- The electric field lines are perpendicular to the equipotential surfaces.
- The potential difference between two points is independent of the path taken.
- A capacitor stores energy in the electric field between its plates.
Remember to practice solving numerical problems to reinforce your understanding.
