Purpose: Map electric equipotential lines and electric field lines for two dimensional
charge configurations
Theory:
The magnitude of electrostatic force between two point charges can be determined
using Coulomb’s
...
Purpose: Map electric equipotential lines and electric field lines for two dimensional
charge configurations
Theory:
The magnitude of electrostatic force between two point charges can be determined
using Coulomb’s law: F=k|q1 q2|
r
2 where r is the distance between charges and
k is the Coulomb’s constant (k=9.0x109 Nm2/C2).
The directions of the forces the two charges exert each other are always along the
line joining the two point charges and like charges repel and unlike charges repel.
The magnitude electric field is defined as the electrical force per unit charge, i.e.,
E=F/q(N/C), here q is a test point charge.
In the case of the electric field associated with a single source charge Q, the
magnitude of the electric field a distance r away from the source charge is the
following equation: E= F
q
=k|q|
r
2 .
Electric field is a vector quantity which is specified by both its magnitude and
direction
The electric field of a point charge always points away from a positive charge but
towards a negative charge.
Figure 1 (a) shows the electric field vectors from a positive source charge. By
drawing lines through the points in the direction of the field vectors, we form the
electric field lines (Fig. 1b and c), which give a graphical representation of the
electric field.
It can be shown that the electric potential at a distance r form the source charge Q
is V=k q
r
.
The electric potential is a scalar quantity, which is specified by its magnitude only.
Electric potential can be either positive or negative depends on the sign of the
source charge Q
The electrical potential of two or more point charges is simply the algebraic sum
of the potentials due to each point charge separately V=k∑
i=1
N Qi
r
i
where N is
the total number of point charges.
Since a free charge is an electric field by the action of the electric force, we say
that work is done by the field on moving a charge from one point to another.
To move a positive charge from B to A would require work supplied by an
external force to move the charge against the electric field.
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