Summary OCR A level Physics A 6.2 Electric fields

6.2 Electric
Fields

, Electric Field Strength
Defined as the force experienced per unit positive charge
F- =
f-
\


field strength
"
E. electric ,
in newtons per coulomb NC ,


f , force in newtons N
, ,


C
Q , charge in coulombs, ,




the direction of an electric field at a
given point is the direction
in which a positive charge would move at that point
Electric field Patterns

•
Arrows show direction of field
Field lines always at
right angles to surface of conductor
•




•

Equally spaced parallel field lines represent a uniform electric field
,


•
The closer the
field lines the greater the strength of the field
,




for radial electric fields ,
the field strength decreases with distance from
the centre

Coulomb 's Law

Any two point charges exert an electrostatic electrical force on each
other that is
directly proportional to the product of their charges and inversely
proportional to the square of the distance between them



According to Newton 's third law the , point charges
exert equal and opposite forces on each other


F ✗
Qq f ✗
¥