Electric field strength between charged plates

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Cici2017

Homework Statement


Multiple-choice physics question diagram showing two parallel conducting plates, positive charges on top and negative on bottom, with line XY perpendicular between them; four graphs of electric field E against distance from X to Y, labelled A to D.


Homework Equations

The Attempt at a Solution


E=kq/r2
so when the distance increase E should decrease?
I know this is wrong, but can someone explain why? Thanks
 
Cici2017 said:

Homework Statement


View attachment 208034

Homework Equations

The Attempt at a Solution


E=kq/r2
so when the distance increase E should decrease?
I know this is wrong, but can someone explain why? Thanks
Have you tried sketching the field lines?
 
haruspex said:
Have you tried sketching the field lines?
field lines are from + to negative. vertical.
 
Cici2017 said:
field lines are from + to negative. vertical.

The field strength is equal to the density of the field lines, what can you say about that if all the field lines are vertical?
 
Cici the field at any point depends, amongst other things, on the geometry of the system. The equation you used gives the field due to an isolated point charge. And yes,this particular field does weaken with distance. The field for other geometries is different so for your parallel plates take the advice given above.