Electrostatics Study Notes Part -1 for Electrical Engineering

In this article, you will find the Study Notes on Electrostatics-Part 1 which will cover the topics such as Force of interaction between two charged particles, Electric Field due to Infinite Line Charge, Electric Field due to Uniformly Charged Ring, Electric Field due to Infinite Sheet of Charge, Superposition Principle of Fields,Electric Flux, Electric Potential, Dipole Moment, Electric flux lines and Electric field due to Dipole. 

• Coulomb’s Law describes the electrostatic interaction between two charged particles.
• It can be derived by combining the equation for the electric field around a spherical charge.
• According to Coulomb’s law, the force acting between two point charges is:
  • directly proportional to the magnitude of each charge,
  • inversely proportional to the square of the separation between their centres, and
  • directed along the separation vector connecting their centres.

• The force acting between two electric charges is radial, inverse-square, and proportional to the product of the charges.
• It is an inverse-square law, given by:

(OR)

F₁₂= (k_e Q₁ Q₂) / r²

• where Q₁ and Q₂ are the magnitudes of the two charges respectively and r is the distance between them, F₁₂ is the force on particle 1 from particle 2, k_e is called as Coulomb’s constant (k_e = 8.99×109 N m² C^-2), and ε₀ is vacuum permittivity (8.85 × 10⁻¹² C²/Nm²).
• F₁₂ = –F₂₁ and |F₁₂| = |F₂₁|, it means that force acting on charge Q₂ due to Q₁ is always equal to the force acting on charge Q₁ due to Q₂ magnitude but opposite in direction.
• The signs of Q₁ and Q₂ must be taken into account means for same polarity charges Q₁Q₂ > 0 and for opposite polarity charges Q₁Q₂ < 0.
• Coulomb’s force obeys law of superposition.
• Note that when both particles have the same sign of charge then the force is in the same direction as the unit vector and particle is repelled.
• The SI unit of electric charge is the coulomb (C)

Force per unit charge is called electric field intensity