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11 Electrostatics
E for an infinite non-conducting sheet
E =
σ
2ε 0
(11.5)
E for an infinite conducting sheet
E =
σ
ε 0
(outside the sheet)
= 0
(inside the sheet)
(11.6)
Electric Potential
When a test charge q 0 is moved from point A (at potential V A ) to the point B (at V B )
then the difference in electric potential is defined by the work done W AB by the
relation
V B − V A = W AB /q 0
(11.7)
If V B > V A , W AB is positive and if V B < V A , W AB is negative. By convention
V A = 0 when A is at infinite distance. Then the work required to move the test
charge q 0 from infinity to the field point is
V = W/q 0
(11.8)
Potential and field strength
V B − V A = W AB /q 0 = Ed
(11.9)
where d is the distance of separation
Potential due to a point charge
V = Er
(11.10)
V =
1
4πε 0
q
r
(11.11)
Potential due to a group of charges
V =
n
V n = V =
1
4πε 0
q 0
r n
(11.12)
Potential due to uniform charge distribution in a non-conducting sphere
11 Electrostatics
E for an infinite non-conducting sheet
E =
σ
2ε 0
(11.5)
E for an infinite conducting sheet
E =
σ
ε 0
(outside the sheet)
= 0
(inside the sheet)
(11.6)
Electric Potential
When a test charge q 0 is moved from point A (at potential V A ) to the point B (at V B )
then the difference in electric potential is defined by the work done W AB by the
relation
V B − V A = W AB /q 0
(11.7)
If V B > V A , W AB is positive and if V B < V A , W AB is negative. By convention
V A = 0 when A is at infinite distance. Then the work required to move the test
charge q 0 from infinity to the field point is
V = W/q 0
(11.8)
Potential and field strength
V B − V A = W AB /q 0 = Ed
(11.9)
where d is the distance of separation
Potential due to a point charge
V = Er
(11.10)
V =
1
4πε 0
q
r
(11.11)
Potential due to a group of charges
V =
n
V n = V =
1
4πε 0
q 0
r n
(11.12)
Potential due to uniform charge distribution in a non-conducting sphere