Electrostatics - Electrostatics Coulombs Law

Electrostatics Coulombs Law

F ∝ q₁q₂, F = q₁q₂/4πε₀r² in free space. 

{ε₀ is permittivity of free space}

F = q₁q₂/4πε₀εrr²

In a medium of relative permittivity εr

1/4πε₀ = 9 x 10⁹ Nm²C^-2

And ε₀ = 8.85 x 10^-12 C²N^-1 m^-2

ε_{r =}  ε_medium  / ε₀ 
   

Where ε_r is dimensionless

Coulomb’s law is valid if r ≥ 10^-15m and charges are point charges or spheres.

Dielectric is an insulator. It is of two types polar or non-polar. Polar dielectrics are those which have permanent electric dipole moments like water. Dielectric constant or relative permittivity for water is 80. It is∞ for metals (infinite). 

Electric field:-  is the region or space around a given charge in which its influence can be detected. 

Electric field intensity:-  or electric field strength is the force experienced by a unit positive charge at that point in the eclectic field of a given charge. Its unit is N/C or V/m

E = Q/4πε₀r² = F/q

In vector form E = Qr/4πε₀r³

There are three types of electric vectors namely E, P and D

Where D = ε₀ E + PD ---> Electric displacement 
             
P = ε₀ (K – 1) EP ---> Polaring vector

For vacuum K = 1 

Electrets do not follows P = ε₀ (K – 1) E

Further E = dV/dr    

Where V is electric potential.

For equipotential surface 

E = 0 

If charge is not a point charge then the linear charge density λ = Q /I surface charge density σ = Q / Area or volume charge density P = (Q /volume) is determined. A small length dx (for linear charge), a small area ds (for surface charge density) is considered in order to find a point charge. We need to write electric force or electric field with it and integrate for total force / field. Electric field obeys superposition principle. 

Electric lines of force are imaginary lines originating from positive charge and terminating at negative charge such that, tangent at any point gives the intersect each other. 

Electric flux: - the electric lines of force passing through any area in an electric field are known as electric flux.

∅ = ∫ E, dS, if E and S are mutually perpendicular then 

∅ = 0, the unit of electric flux is Nm²C^-1 and dimensions are ML³T³A^-1 it is a scalar quantity. 

Electrostatics Coulombs Law Assignment Help, Electrostatics Coulombs Law Homework Help, Electrostatics Coulombs Law Tutors, Electrostatics Coulombs Law Solutions, Electrostatics Coulombs Law Tutors, Electrostatics Help, Physics Tutors, Electrostatics Coulombs Law Questions Answers