However, if a charge q is brought
at any point around Q, Q itself is bound to experience an electrical
force due to q and will tend to move A way out of this difficulty is to
make q negligibly small The force F is then negligibly small but the
ratio F/q is finite and defines the electric field:
E
F
=


→
qlim
q
0
(1 9)
A practical way to get around the problem (of keeping Q undisturbed
in the presence of q) is to hold Q to its location by unspecified forces