All Questions
Tagged with electric-fields potential-energy
142
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Zero Electric Potential but non-zero Electric field?
A point P at the exact half way of two opposite charge will have zero potential (assume potential is set zero at infinity) ,but the electric field will not be zero at point P. How to completely ...
- 13
1
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5
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427
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Why is the potential not infinite?
One way to calculate potential (using infinity as our reference point) is to sum all the contributions of charges that are around.
Let's say I want to calculate the potential at some point on charged ...
- 105
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48
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Potential energy of a system of three charges question
Two point charges are located on the $x$-axis, $q_{1}=-e$ at $x = 0$ and
$q_{2} = +e$ at $x = a$.
(a) Find the work that must be done by an
external force to bring a third point charge $q_{3} = +e$ ...
2
votes
2
answers
862
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Minimizing electric potential means potential difference is zero
I had been working on a problem recently and i stumbled upon something I did not quite get. So the relevant part of the problem is like this:
Suppose we have two conducting spheres with radii a and
b ...
- 143
1
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2
answers
80
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How to make sense out of Potential Energy?
My teacher says that Energy is in the form of Electric field. I've also seen the mathematical prove. (The amount of work done in bringing a charge from infinity to that point in the Electric Field) ...
- 63
1
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133
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Work $U$ required to assemble a charge distribution
I'm reading Purcell's Electricity and Magnetism (p. 72) and it gives an relation between the work $U$ required to assemble a charge distribution $ \rho (x,y,z) $ and potential $\phi (x,y,z) $ of that ...
- 159
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35
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Potential Energy of two charges which are not fixed
Suppose I have 2 charges (+q and +Q) which remain fixed and are placed at a seperation R. They will have some Potential Energy which is kQq/R.
So I wanted to ask that if the charges are not fixed then ...
- 63
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354
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Change in potential / potential energy of a charge in electric field [closed]
A uniform electric field of 2000 $(\frac V m)$ exists through all space (the field is in $+x$ direction). An electron is moved from the origin to the location where $x = -2.00 (m)$ and $y = +3.00 (m)$....
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1
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526
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How is the reference point of potential energy defined in electric fields?
Consider the diagram below of a positive charge and three points marked in the field X, Y and Z.
I understand that for a gravitational field, we define the potential energy as being always negative, ...
- 323
2
votes
4
answers
491
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How can we have negative work in electrostatics, if $W=(\epsilon_0/2)\int\! E^2\ \mathrm{d}\tau$?
This question is motivated by Section 3.2.3 in Griffiths.
Therein, we are considering the force of attraction between a point charge and an infinite conducting plane. One can calculate the field ...
2
votes
2
answers
185
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Electric potential and electric potential energy
I have a simple question about the electric potential and electric potential energy.
The gradient of the electric potential gives us the electric field,
and the gradient of the electric potential ...
- 47
-2
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4
answers
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Potential Energy of a Electric Dipole
I am trying to derive the potential energy because of torque in a dipole placed in a uniform electric field. But the answer I am getting is different from the answer I saw everywhere. So could someone ...
- 307
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2
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108
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Why is $U_e=-W$?
Electric potential energy $U_e$ is defined as $k_e\frac{Q_1Q_2}{r}$. From that we get:
$$U_e=k_e\frac{Q_1Q_2}{r}=ErQ_2=F_er=W$$
Now, a lot of sources claim that $U_e=-W$. Why is work negative in this ...
- 167
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1
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206
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Relation between the energy of a capacitor and the force it applies [closed]
I have a capacitor with stored energy $U$. I do not understand the relation $\vec{F}=-\vec\nabla U$, where $\vec{F}$ is the force that the capacitor applies on the charge inside it.
- 555
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How can net potential energy for a charged particle be 0 but still have a net electric field [duplicate]
Im studying charged particle and i recently came up with a question that stated that a charge was released from a position in which had no electric potential but however accelerated due to a electric ...
