The Physics
Opus in profectus

Electric Field

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Some text and some diagrams. The electric field as a vector field.

And more diagrams. The electric field as field lines.

And maybe some mathematics. In classical field theory, the strength of the field at a point is the normalized value of the field. In other words…

field =  force

For electricity, this becomes…

E = FE

There is no special name for its unit, nor does it reduce to anything simpler.

N  =  kg m/s2  =  kg m

C A s A s3

We will see later that this is equivalent to…

N  =  V

C m

For point charges…

E =  1   q   or E = k  q  
4πε0   r2 r2

For multiple point charges…

E =  1  ∑  dq   or E = k ∑  dq  
4πε0 r2 r2

For continuous charge distributions…

E =  1
dq   or E = k
4πε0 r2 r2
Electric field strength (smallest to largest)
E (V/m) device, event, phenomenon, process
5.0 × 10−7 shark, threshold of sensitivity
120 earth's surface (sea level)
3 × 106 dielectric breakdown of air