Tagged Questions
5
votes
4answers
192 views
Energy Gain with capacitor?
I have a question about energy gain in capacitors. Assume the following system:
As the electron gets accelerated inside the capacitor, it will have more kinetic energy coming out than going in. But ...
0
votes
2answers
57 views
Why does the area of the plates affect the capacitance?
Why does the area of the plates affect the capacitance? Lets say I have a parallel plate capacitor with a charge of 10C and a potential difference of 5V. By the definition $C=Q/V$, the capacitance is ...
0
votes
1answer
48 views
Where are exactly the charges of charged capacitor?
a capacitor is connected to a battery and is charged, are there charges inside the wires or they just accumulate on the surfaces of capacitor?
0
votes
2answers
59 views
Why isn't this capacitor charging?
Let's say you have a parallel plate capacitor and you connect one plate to the positive terminal of a battery and the other plate to the negative end. So this is like a static situation, you have a ...
1
vote
3answers
134 views
Can I charge a capacitor using 2 batteries?
1 capacitor, 2 separate batteries (Battery A and Battery B).
Connect A+ to one side of the capacitor and B- to the other side of the capacitor.
A and B are not connected, there is no closed circuit.
...
0
votes
0answers
121 views
Energy stored in charge capacitor [closed]
Two identical parallel-plate capacitors, each with capacitance $C$, are charged to potential difference $V$ and connected in parallel. Then the plate separation in one of the capacitors is doubled.
...
1
vote
1answer
136 views
Parallel capacitors without battery. Does charge flowing after a dielectric input?
If I charge two capacitors which are connected parallel $[$the minus (-) of the one opposite to the minus (-) of the other and the plus(+) of the one opposite to the plus (+) of the other.$]$, will I ...
0
votes
1answer
221 views
Non conducting charged planes
I have two parallel non conducting charged planes with opposite charges $6\mu C/m^2$, area $A = 3m^2$ and distance between the planes $d = 0.004 m$. I know the potential between these two planes is ...
1
vote
1answer
42 views
What happens to this energy of the capacitor?
Let's say you have a charged, isolated parallel plate capacitor with a certain voltage. My book says that if you insert a dielectric, the voltage drops. However, that would require the energy between ...
2
votes
4answers
103 views
Capacitance of a capacitor
Why does the capacitance of a capacitor increase if the distance between the two plates of a parallel plate capacitor is decreased? I think, with decreasing distance between the two plates, the force ...
8
votes
3answers
322 views
Where's the energy in a boosted capacitor?
Suppose I look at a parallel plate capacitor in its rest frame and calculate the electrostatic energy, $E$.
Next, I look at the same capacitor in a primed frame boosted in the direction perpendicular ...
1
vote
2answers
90 views
How can you calculate (or convert) the Wh of a capacitor whose energy is given in Farads
When trying to compare the energy in a battery to the energy in a capacitor, the units don't match up. How can one compare a battery whose Ah are 10 and Voltage is 3 (for a total of 30 Wh) to a ...
0
votes
1answer
88 views
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them?
Is it possible to charge a capacitor to any potential? Does it depend on the dielectric placed between them? Or, are there other factors affecting it?
5
votes
1answer
514 views
What defines the maximum charge a capacitor can store?
The formula for a capacitor discharging is $Q=Q_0e^{-\frac{t}{RC}}$
Where $Q_0$ is the maximum charge. But what property defines the maximum charge a capacitor can store?
If it depends on ...
3
votes
1answer
435 views
What is the role of battery across a Parallel plate capacitor having equal charge?
Each plate of a parallel plate capacitor has a charge $q$ on it. The capacitor is now connected to a battery. Now, which of the following options are correct?
a) The facing surfaces of the ...
0
votes
1answer
48 views
Charging using a CRT TV set
I was doing an experiment with my CRT TV where I put aluminum foil on the screen wire it to a can and open the TV and a ring between 2 can will swing if I ground the other can. ...
3
votes
2answers
461 views
If we charge a capacitor can we discharge it into a battery?
I have read that we can charge a capacitor using a battery, but can the vice versa happen? My project needs to show a battery being charged through a fully charged capacitor.
0
votes
1answer
152 views
Charge on capacitor plates in series combination?
Suppose 2 capacitors are connected in series, the plates connected to the battery terminals receive charges $+q$ and $-q$, and the isolated plates in the combination receive equal and opposite charges ...
3
votes
1answer
52 views
Unrolling electrolytic capacitors
If I take an electrolytic capacitor, remove the aluminium casing, unroll the foil/ electrolyte-soaked paper, if charged, will it still work? And what if I took of the cathode foil and wrapped the ...
0
votes
1answer
94 views
Will I recieve a shock if I charged a capacitor then i touch the 2 poles in same time?
What happens if I charged a capacitor then i touch the 2 poles in same time?
2
votes
1answer
310 views
how to calculate electric relative permittivity of fluid or medium
I am confusing in calculating permittivity of the fluid. Permittivity differs from one fluid to another.
$$\varepsilon=\varepsilon_r\varepsilon_0$$
Since it is an electrical property combined with ...
0
votes
1answer
46 views
Can we transfer the charge on a plate of a capacitor elsewhere?
I know it is hard , but can we transfer the charge on a capacitor plate elsewhere?
0
votes
0answers
111 views
Charging a metal plate
I am supposed to find a way to charge a metal plate with a defined charge ( in nanocoulomb) and it must have a + charge so basically i want to know if this way is correct and applicable, and if there ...
0
votes
1answer
46 views
Charge of an electrolytic capacitors
I can't understand the electrolytic capacitors, when a capacitor has a capacitance of 100 microfarads, does that mean that when it is charged with 100 volts will the charge of the plate be 0.01 ...
0
votes
1answer
107 views
Will the plates of a parallel plates capacitor keep its charge after being charged then seperated from the non- conductor?
If i had 3 plates 2 metals and 1 glass .I put them together to form a basic parallel plates capacitor.
After charging it and approaching it to an electroscope nothing happened that's because ...
0
votes
2answers
150 views
Effect of charges near a parallel plate capacitor
If I charged a parallel plate capacitor. And then, I insert a charged body near one of the plates.
Will there be any interactions like attraction or repulsion?
What if I disconnected the battery?
6
votes
0answers
222 views
Capacitance of this unusual capacitor
This capacitor is composed of two half spherical shelled conductors both with radius $r$. There is a very small space between the two parts seeing to that no charge will exchange between them.
...
1
vote
1answer
163 views
Why is water not used as a dielectric in the condenser?
The dielectric constant of water is very high. Then why is it not used as a dielectric in the condenser?
2
votes
2answers
147 views
Energy in electric field
I'm having some trouble understanding a homework question and would appreciate some help.
The question is as follows:
Jenny charges a capacitor with the help of a battery. She then removes
the ...
4
votes
3answers
238 views
Change in attraction of charged bodies
If I insert a piece of glass between two objects carrying different charges, would they still attract?
If they attract, does the piece of glass affect the force of attraction and is there any formula ...
5
votes
3answers
229 views
A problem of missing energy when charging a second capacitor
A capacitor is charged. It is then connected to an identical uncharged capacitor using superconducting wires. Each capacitor has 1/2 the charge as the original, so 1/4 the energy - so we only have 1/2 ...
12
votes
4answers
549 views
Is there a deep reason why springs combine like capacitors?
I was solving a practice Physics GRE and there was a question about springs connected in series and parallel. I was too lazy to derive the way the spring constants add in each case. But I knew how ...
1
vote
2answers
277 views
Proof of charge existence on a grounded conductor
A question regarding the existence of charge on grounded conductors is confusing me.
Could there be charge on a grounded conductor?
How does this not contradict Gauss's Law?
Since every conductor ...
0
votes
3answers
455 views
When I connect two charged capacitors side by side, what will be the voltage across them?
Say, I have two charged capacitors, one 3mF and one 2mF. The voltage across them are 20V and 30V respectively. Now if I connect the two capacitors side by side as shown below, what will be the voltage ...
6
votes
4answers
2k views
Will a charged capacitor discharge if one lead is connected to ground?
If I charge a capacitor and connect one lead to ground keeping the other lead floating, will the capacitor discharge ?
...
1
vote
4answers
292 views
Why does it seem that the potential difference dependence of capacitance and total energy stored in a parallel-plate capacitor are contradictory?
Consider a parallel-plate capacitor. Charge is stored physically on electrodes ("plates") which are flat and parallel to one another. If one electrode has charge $+Q$ and the other electrode has ...
2
votes
5answers
3k views
What is the difference between a battery and a charged capacitor?
What is the difference between a battery and a charged capacitor?
I can see lot of similarities between capacitor and battery. In both these charges are separated and When not connected in a circuit ...
0
votes
2answers
68 views
Permitivity $\mathcal{E}$ as a function of Voltage across a medium
What I wanted to Know was is there a change in Dielectric Permitivity constant as the voltage increases.
My question arose from the fact that for a breakdown voltage to be reached the Permitivity ...
1
vote
3answers
2k views
How is calculated the potential between two capacitors in series?
Suppose to have two capacitors in series:
The voltage in the middle point will be:
$$
V_X = V_1 \frac{C_1}{C_1+C_2}
$$
How can this be explained? It's been asked in electronics, and explained in ...
2
votes
2answers
508 views
Charge distribution on a plate of Capacitor with Dielectrics .
I had this Homework Problem with a capacitor (parallel plate) that has a group of 3 dielectrics between it like so :
Now We were asked to find the equivalent capacitance and the distance of ...
1
vote
1answer
258 views
Dielectric in a parallel plate capacitor
Uniform charge: each atom has charge $q$.
Magnitude of dipole moment is $q s$, where $s$ is the distance the nucleus is shifted.
According to my notes, the charge on the surface of a dielectric in ...
-1
votes
3answers
204 views
What's the right way to calculate charge on a capacitor?
How much charge is on each plate of a 4.00-F capacitor
when it is connected to a 12.0-V battery?
I said 2.4 x 10^-5 C because there are two plates of a parallel plate capacitor. But the key said only ...
0
votes
2answers
326 views
Capacitors in series
I need some explanations on the green underlined sentences.
1) "Must continue to have zero net charge..." What if the $\ C_2$ had +2Q on the left plate and -Q its right plate? The net charge ...
1
vote
3answers
330 views
Is this really how a capacitor works? Why doesn't it behave like a resistor?
My book says a capacitor is two conducts being connected by an insulator. Now let's take a parallel plate capacitor to simplify the problem I have.
Suppose I got two parallel plate capacitor in ...
5
votes
3answers
805 views
Charge Distribution on a Parallel Plate Capacitor
If a parallel plate capacitor is formed by placing two infinite grounded conducting sheets, one at potential $V_1$ and another at $V_2$, a distance $d$ away from each other, then the charge on either ...
1
vote
0answers
218 views
Dielectric in Parallel Plate Capacitor
Given a parallel plate capacitor of width $w$, length $l$, with a dielectric moving along the length $l$. Let the dielectric be from $x$ onwards.
The capacitance will be $\frac{w \epsilon_0}{d} ...
2
votes
1answer
424 views
How is capacitance defined for three concentric spheres?
If we have a configuration of metal concentric spheres (each of negligible thickness) of radii $r_1,r_2,r_3$ respectively and $r_1<r_2<r_3$, and we are given the potentials of the spheres to be ...
0
votes
3answers
1k views
Electric field at a point inside a capacitor
Let's say I have a parallel plate capacitor.
How would I find the electric field at a certain point INSIDE the capacitor (inside the dielectric let's say). From what I understand, the flux of the ...
2
votes
4answers
709 views
How does instant charging of one plate affect the potential of the other plate of a floating capacitor?
If I have an uncharged floating capacitor and I instantaneously connect one plate to some potential, then that plate will acquire some charge. In practice, the other floating plate will ...
2
votes
2answers
125 views
Determining the capacitance of a system with a non-homogenous dielectric
In an experiment we were given non-homogenous dielectric substances described by functions of coordinate. How can capacitance be determined from this?
