Find the direction of a electric field

[Zanatos]

Hey, My problem is that I am getting confused (although getting the answer right ) on how to find the direction of a electric field, for example (right or left). I know it has something to do with a test charge but can anyone quickly explain it to me.

~THX

 

[chanvincent]

Imagine the electric field as a banch of arrows (vector), the field ALWAYS points OUT from the POSITIVE charge and points INTO the NEGATIVE charge...

The force acts on the test charge follows the direction of the E-field if the test charge is POSITIVE, and oppose to the field if the test charge is NEGATIVE...

 

[fffff]

Its easy mate, Electric field lines are directed from the higher potential to the lower potential.

So assume we have two plates, A and B. Assume B is earthed ( 0V) and plate A is at a potential of -200V.

So what would be the direction of the elctric field. From A to B or B to A.