Like the electric field at a point in
space due to a single charge, electric field at a point in space due to the
system of charges is defined to be the force experienced by a unit
test charge placed at that point, without disturbing the original
positions of charges q1, q2, , qn We can use Coulomb’s law and the
superposition principle to determine this field at a point P denoted by
position vector r Rationalised 2023-24
16
Physics
Electric field E1 at r due to q1 at r1 is given by
E1 = 
41
0
1
1
2
πε
q
r P
1P
ˆr
where 
1P
ˆr  is a unit vector in the direction from q1 to P,
and r1P is the distance between q1 and P