Electric Charges and Fields

Electric Charges

• Electric charge is a fundamental property of matter that can be positive or negative.
• Like charges repel each other, while opposite charges attract each other.
• The unit of electric charge is the coulomb (C).
• Electric charge is quantized, meaning it comes in discrete packets called electrons.

Types of Electric Charges

• Positive charge: carried by protons, which reside in the nucleus of an atom.
• Negative charge: carried by electrons, which orbit the nucleus of an atom.

Electric Field

• An electric field is a region around a charged particle or object where the force of the charge can be detected.
• Electric field is a vector quantity, denoted by E.
• The unit of electric field is newtons per coulomb (N/C).
• Electric field lines:
  • emerge from positive charges and enter negative charges.
  • are continuous and never intersect.
  • are denser where the field is stronger.

Electric Field Strength

• Electric field strength is the force experienced by a unit test charge at a given point in the electric field.
• Electric field strength is proportional to the magnitude of the charge and inversely proportional to the square of the distance from the charge.

Electric Field Due to a Point Charge

• The electric field due to a point charge is given by Coulomb's Law:
  • E = k * q / r^2
  • where E is the electric field strength, k is Coulomb's constant, q is the charge, and r is the distance from the charge.

Electric Field Lines for Different Charge Configurations

• Single point charge: radial electric field lines emerge from or enter the charge.
• Two point charges: electric field lines are distorted and interact with each other.
• Dipole: electric field lines emerge from the positive charge and enter the negative charge, forming a loop.