Physics

Introduction to Electricity & Electrostatics

Electricity involves the movement of electric charges, whereas electrostatics studies stationary charges and the forces between them. These concepts are foundational for understanding electric circuits, fields, and potential.

Core Concepts

Electric Charge

Fundamental property of matter; can be positive or negative.

Electric Field

Region around a charge where force is experienced.

Electric Current

Rate of flow of electric charge in a conductor.

Important Equations

F = k * q₁q₂ / r²

Coulomb's Law

E = F / q

Electric Field

V = IR

Ohm's Law

P = VI

Electric Power

Electric Circuits & Electrostatics Applications

Capacitors: Store electrical energy in an electric field.
Resistors: Oppose current flow and regulate voltage.
Static Electricity: Caused by imbalance of electric charges.
Lightning: Example of electrostatic discharge in nature.

Example Problems

1. What is the force between two 1 μC charges 1 m apart?

Solution: F = 9×10⁹ × (10⁻⁶)² / 1² = 0.009 N

2. A bulb uses 2 A current with 12 V supply. Find its resistance.

Solution: R = V/I = 12 / 2 = 6 Ω

3. Calculate power used by a device drawing 3 A at 220 V.

Solution: P = VI = 220 × 3 = 660 W

ELECTRICITY

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