Everything electrostatics

[canadianofpeace]

So these are confusing me, I have the following notes written down.

Electric Fields due to a Point Charge
E = k q1 / r2
P.E. = k q1 q2 / r
V = k q1 / r

Constant Electric Fields
F = E q
V = E d
P.E. = q E d
P.E. = V q

I have completely confused myself and need help with the basics. First of all, when it says electric field due to a point charge would that mean say the field an electron feels due to a point charge which is some distance away? So when I have this type of scenario I would use the first batch of equations?

While talking about constant electric fields, are those usually referring to parallel plate capacitors and what not? I suppose I am just more confused as to what the difference here is and how to tell right away. For the sake of the MCAT is it safe to assume scenario two is mainly just for when the question explicitly says constant E, and capacitor like scenarios?

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[gettheleadout]

So these are confusing me, I have the following notes written down.

Electric Fields due to a Point Charge
E = k q1 / r2
P.E. = k q1 q2 / r
V = k q1 / r

Constant Electric Fields
F = E q
V = E d
P.E. = q E d
P.E. = V q

I have completely confused myself and need help with the basics. First of all, when it says electric field due to a point charge would that mean say the field an electron feels due to a point charge which is some distance away? So when I have this type of scenario I would use the first batch of equations?

The electric field due to a point charge represents (by convention) the vector force experienced by a test charge (a single positive charge) located within the field, so while an electron would experience the field in the same manner, the direction of the force upon the electron will be opposite that of the field vectors/lines.

While talking about constant electric fields, are those usually referring to parallel plate capacitors and what not? I suppose I am just more confused as to what the difference here is and how to tell right away. For the sake of the MCAT is it safe to assume scenario two is mainly just for when the question explicitly says constant E, and capacitor like scenarios?

The term "uniform" electric field is often used as well. By definition a uniform electric field (where all field lines are parallel) has equal field strength at all points and so is "constant" in strength. The field present in the gap/dielectric between the parallel plates of a capacitor is a common example. A hypothetical infinite planar charge distribution works as well. because constant electric field strength requires uniformity of the field, yes, you can visualize a uniform electric field if a question indicates that E is constant throughout the field.