Concept of electric field
Charge distribution
Test charge=2nC
F=300nN
Electric field at P =
P
CNnC
nN
q
F/150
2
300
0
E=150N/C
q=-4nC
Force on q =
NCNCqE 99 10600)/(150)(104
600nN
a
+q
-q
-q
-q
What is electric field at center ?
EA
A B
CD
EB
ED
EC
E
Electric dipole
Field lines of two equal charges
Michael Faraday (1791-1867)
electric field line video