DC Circuits Fundamentals of Electricity

Coulomb’s Law and Electric Charge in Electricity

According to physics terminology, electric charge experience force when kept in a magnetic field.

Here electric charge is in the form of matter which may be the positive charge or negative charge. Positive charge is the composition of protons and negative charge contains electrons. When protons or electrons move in the electric field they produce electric current.  Here are some properties of electric charge.

Properties of Electric Charge

  • Law of conserving charge states that charge or energy is neither created nor destroyed. It is in the form of charged objects that influence nearby objects (charged or uncharged).
  • Charge is a Scalar quantity and its units are Coulombs.
  • The movement of charges is free through the conductors and do not conducts through the insulator.
  • When the size of charged objects is small than the distance between them, they are called the point of charges.
  • Charges can be added together having a magnitude with no direction.

Coulomb’s Law

Coulomb’s law in electricity signifies the importance of point of charges.

It was invented by Charles Augustin de Coulomb. He observed that an electric force exists around different charges.

Definition of Coulombs Law

  • Coulomb’s Law states that “the force existing between the two point charges varies inversely as the square of the distance between them.
  • The force was directly proportional to the multiple of charges and also acts on the area joined by the two charges.

In simple words, if two charges Q1 and Q2 are separated by distance ‘R’ they produce force.

Coulumbs Law

The formula or equation for coulombs law is given by the equation

F= Z x |C1xC2|/ R


F‘ represents the Force generated between the two charges

Z‘ is the Coulomb Constant which is equal to 8.99×109 N m2 C2

C1‘ and ‘C2‘ represents magnitude of charges

R‘ is the distance between the two charges

Note: If the magnitude of charges is opposite then Force is negative in nature and if the magnitude is same the force is positive.


  • In static charge analysis
  • For grounding and protecting the electronic components from electrostatic discharge
  • To find out the distance between the charged or uncharged particles.

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