Electric Charge

Electric Charge:

• • What is Electric Charge?
    Electric charge is a fundamental property of matter that causes it to experience a force when placed in an electric or magnetic field. There are two types of electric charges: positive (+) and negative (-). Like charges repel each other, while opposite charges attract each other.

  • Unit of Electric Charge:
    The unit of electric charge is the coulomb (C). One coulomb is approximately equal to 6.242 × 10¹⁸ elementary charges (the charge of a single electron or proton).

  • Quantization of Charge:
    Electric charge is quantized, meaning it comes in discrete amounts. The smallest possible charge is the elementary charge (denoted as e), which is about 1.602 × 10⁻¹⁹ C. All charges are integral multiples of this elementary charge.

  • Types of Electric Charge:

    • Protons: Positive charge (+e).
    • Electrons: Negative charge (-e).
    • Neutrons: Neutral (no charge).

  • Conservation of Charge:
    Electric charge is conserved, meaning the total charge in a closed system remains constant. Charge can be transferred between objects but cannot be created or destroyed.

Coulomb’s Law:
Coulomb’s Law explains the force between two point charges and is given by:

F = k × |q₁q₂| / r²

Where:

• • • F is the force between the charges,
    • q₁ and q₂ are the charges,
    • r is the distance between the charges,
    • k is Coulomb’s constant (8.99 × 10⁹ N·m²/C²).

The force is attractive if the charges are opposite and repulsive if the charges are the same.

• Electric Field (E):
  An electric field is a region around a charged object where other charges experience a force. The field’s direction is the way a positive test charge would move. The strength of the electric field depends on the charge and the distance from it:

  E = F / q

  Where:

  • F is the force,
  • q is the test charge.

• Conductors and Insulators:

  • Conductors (e.g., metals) allow electric charges to move freely through them.
  • Insulators (e.g., rubber, glass) do not allow electric charges to move freely.

• Charging Methods:

  • Friction: Rubbing two objects together causes a transfer of electrons (e.g., rubbing a balloon on your hair).
  • Conduction: Direct contact between two objects allows charges to transfer.
  • Induction: A charged object can induce a charge in a nearby neutral object without direct contact.

• Applications of Electric Charge:
  Electric charges are used in many devices, such as batteries, capacitors, and electric circuits. They also play a role in electrostatic phenomena, like lightning and photocopiers.

• Electric Potential and Potential Energy:
  Electric potential (or voltage) is the amount of electric potential energy per unit charge at a point. The potential energy of a charge in an electric field depends on its position relative to other charges.

• Electron and Proton Mass Comparison:
  Electrons have a very small mass (9.11×10−31kg) compared to protons (1.67×10−27kg).