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Electric field and potential

A charge creates an electric field in the space around it, and the field exerts a force on other charges located there. The potential (voltage) is energy per charge: a charge moving through a potential difference gains or loses the energy $qU$ .

E = F/q

electric field, force per charge

E = U/d

field between parallel plates

U = W/q

potential (voltage), energy per charge

Symbols

$E$	electric field	N/C
$U$	voltage	V
$d$	distance between the plates	m

Example

Two parallel plates with $U = 400$ V are $d = 0.02$ m apart. The field between them is $E = 400/0.02 = 20.000$ N/C.

The field between parallel plates is approximately uniform and given by

E = U/d

, regardless of where between the plates you are.

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Part of Physics: Electricity and magnetism.