House of IT

  12.1 COULOMB’S LAW   COULOMB’S LAW    Statement :    The electrostatic force between two point charges is directly proportional to the product of the magnitude of charges and inversely proportional to the square of distance between them.     Mathematical Expression :  If two point charges  q 1 and  q 2  are separated by a  distance  r , then the electrostatic force ‘ F ’ between them is expressed as:   F = k q 1 q 2 r 2     where   k  is the constant of  proportionality and is expressed as   k = 1 4 π ε 0   where   ε 0  is the permittivity of free space and its value in SI unit is  8 . 85 × 10 − 12 C 2 N   m 2 .     VECTOR FORM OF COULOMB'S LAW   The electrostatic force  F ⃗   between two point charges   ‘ q 1 ’ to ‘ q 2 ’ is expressed as:     F ⃗  = 1 4 π ε 0       q 1 q 2 r 2 r ˆ   Here...