Coulumb's law

Electricity

Electric field: It is a region where a charged particle experiences a force

Electric field strength : The force per unit positive charge

EFS in radial field : as E=F/Q, F=Q1Q2/r^2

The law states that the force exerted by two charged particles on each other is directly proportional to the product of their charges and is inversely proportional to the square of the distance between the particles..

Comparison

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E=F/Q and E=V/d

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Gravitational fields

Electric fields

Masses

Only attraction, no repulsion

g = F/m

F in N, g in N Kg-1 or ms-2

g is constant

F=GMm/r2

g=GM/r2

Φ=-GM/r

Electric charges

Attraction AND repulsion

E=F/Q

F in N, E in NC-1 or Vm-1

E=V/d constant

F=Q1Q2/4πεr2

E=Q/4πεr2

V=Q/4πεr