5 A system of
(a) three charges
(b) multiple charges Rationalised 2023-24
12
Physics
 EXAMPLE 1 5
In the same way, the force on q1 due to q3, denoted by F13, is given by
F
r
13
0
1
3
13
2
13
=41
πε
rq q
ˆ
which again is the Coulomb force on q1 due to q3, even though other
charge q2 is present Thus the total force F1 on q1 due to the two charges q2 and q3 is
given as
F
F
F
r
r
1
12
13
0
1
2
12
2
12
0
1
3
13
2
13
41
41
=
+
=
+
π
π
ε
ε
rq q
rq q
ˆ
ˆ
(1