15
votes
Why do we say that electric potential energy is stored in the electric field?
It can be difficult to see why the electric field has to store energy when studying electrostatics alone. Electrodynamics provides the real motivation. As David Griffiths puts in his text Introduction ...
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11
votes
Why do we say that electric potential energy is stored in the electric field?
Here is a simple argument that I find suggestive ...
The capacitance of an 'ideal' vacuum-spaced parallel plate capacitor (one for which the plate dimensions are much greater than the plate separation,...
- 34.9k
8
votes
Why decreasing the distance between a parallel plate capacitor increases the electric field? Wouldn't it remain the same? $\sigma/\epsilon_0 $?
Two possibilities.
1 Charged capacitor not connected to anything else.
Charge,$q$, and hence charge density, $\sigma = q/A$, cannot change.
Electric field $E = \sigma/\epsilon_0 = V/d$ does not change....
- 93.8k
6
votes
Why do we say that electric potential energy is stored in the electric field?
I don't really get why do we say energy is stored in electric field
rather than in the charges upon which we or the battery does work.
It is stored in both. Electrostatic potential energy, just like ...
- 69.1k
2
votes
Why do we say that electric potential energy is stored in the electric field?
There are two things to note here:
Electrons are free to move wherever they like to be within any electrical conductor. The steady state is that they do not feel the urge to move at all (ignoring ...
2
votes
Why do we say that electric potential energy is stored in the electric field?
If you wiggle charges in the right way, they produce electromagnetic waves. These waves can extend for great lengths. For example, the Voyager space probe is a spacecraft that is headed for deep space....
2
votes
Why decreasing the distance between a parallel plate capacitor increases the electric field? Wouldn't it remain the same? $\sigma/\epsilon_0 $?
Starting from the expression of the electric field of a 2-dimensional circular charged plate with radius R. The correct expression for the electric field is $$\mathbf{E}(x)=\frac{|\sigma|}{\epsilon_0\...
- 310
2
votes
Why decreasing the distance between a parallel plate capacitor increases the electric field? Wouldn't it remain the same? $\sigma/\epsilon_0 $?
Assuming a constant potential difference is applied to capacitor, Like battery
Why do you think that The Charge density "sigma" will not change? If you calculate carefully, The electric ...
- 354
1
vote
Accepted
Infinite electrostatic plate acceleration
On way to do this is make your not-so-infinite plate a charge distribution on a disc (aligned on $z$ for reasons):
$$\rho(r, \theta, \phi) = \sigma (1-\Theta(r-R))\delta(\theta-\frac{\pi} 4)$$
Now you ...
- 31.5k
1
vote
For electric field between two parallel plate capacitor given by $Q/A*\epsilon_0$, how does the inverse proportionality of area make sense?
The formula that you've quoted applies to a capacitor for which the plates' dimensions are much greater than their separation.
The result follows almost immediately from Gauss's law and symmetry, ...
- 34.9k
1
vote
Accepted
Why is the potential due to induced charges constant?
From Gauss's law for the point charge (eq. 3):
$$\nabla^2\phi_{\mathbf y}(\mathbf x) = 2\pi q\cdot\delta(\mathbf x - \mathbf y)$$
This is symmetrical in $\mathbf x$ and $\mathbf y$ since $\delta(\...
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