# Eletric field, acceleration

## Homework Statement

I dont have any statement, i have to find the problem statement from the answers
a) E = Q / [ Eo* (0.020 m)^2 ]
b) a = E (1.60*10-19 C)/(1.67*10^-27 kg) = 2.0 *10^12 m/s^2
R=0,020 m
q=1.60*10-19 C
m=1.67*10^-27 kg

## Homework Equations

F=ma => a=qE/m
Gauss Law Integral of (E,ds)=Q/Eo

## The Attempt at a Solution

So given E constant everywhere i can assume that E*(integral of ds)=Q/Eo, so if this was a sphere it would be
4piR^2*E=Q/Eo so its out, my equation must be something like E*R^2=Q/Eo , so my area should be a a square ?,
also E and the trajectory of my q must be parallel right ?
Any helpful hints are really appreciated ;d

## Answers and Replies

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ehild
Homework Helper

## Homework Statement

I dont have any statement, i have to find the problem statement from the answers
a) E = Q / [ Eo* (0.020 m)^2 ]
b) a = E (1.60*10-19 C)/(1.67*10^-27 kg) = 2.0 *10^12 m/s^2
R=0,020 m
q=1.60*10-19 C
m=1.67*10^-27 kg

## Homework Equations

F=ma => a=qE/m
Gauss Law Integral of (E,ds)=Q/Eo

## The Attempt at a Solution

So given E constant everywhere i can assume that E*(integral of ds)=Q/Eo, so if this was a sphere it would be
4piR^2*E=Q/Eo so its out, my equation must be something like E*R^2=Q/Eo , so my area should be a a square ?,
also E and the trajectory of my q must be parallel right ?
Any helpful hints are really appreciated ;d

## The Attempt at a Solution

So given E constant everywhere i can assume that E*(integral of ds)=Q/Eo, so if this was a sphere it would be
4piR^2*E=Q/Eo so its out, my equation must be something like E*R^2=Q/Eo , so my area should be a a square ?,
also E and the trajectory of my q must be parallel right ?
Any helpful hints are really appreciated ;d[/QUOTE]
You guess well, it might be the constant electric field of a a charged square-shaped plate, or rather the electric field between the plates of a planar capacitor with charge Q, where the plates of the capacitor are squares of sides 0.02 m.
The trajectory of the particle with charge q need not be parallel to E, but its acceleration has to be. What do you think the particle is?

Zbud
Given its mass and charge it must be certainly a proton, i have been thinking about the capacitor but truly as we have not talked about it once during the lectures so I wasnt keen on that idea,I'm grateful for your insight into this unusual problem

ehild
Homework Helper
Given its mass and charge it must be certainly a proton, i have been thinking about the capacitor but truly as we have not talked about it once during the lectures so I wasnt keen on that idea,I'm grateful for your insight into this unusual problem
That is correct, it must be a proton. Well done!
In case of single charged plate, the electric field is Q/(2Aε0), but it is Q/(Aε0) in case of a capacitor.