The ability of an object to store electric charge.

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Drawing electric field lines-Equations or software

Shown below in the diagram are two conducting material connected to a battery source and vacuum OR air is in between them. There will be charges developed on their surfaces. I am interested in finding ...
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1answer
1k views

Electric field in a capacitor with a dielectric with variable permittivity

Consider the following parallel-plate capacitor, with a potential difference of $V$ across it's plates: I've seen some problems that assume a dielectric with a variable electric permittivity of ...
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990 views

What are the advantages in using 2 identical capacitors?

What advantage might there be in using two identical capacitors in parallel connected in series with another identical parallel pair, rather than using a single capacitor?
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3answers
653 views

Which is more dangerous upon contact, series or parallel capacitors?

If a pair of capacitors were connected up in series, and an identical pair was connected in parallel which pair would be more dangerous to handle if connected to the same voltage source?
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1answer
1k views

Dipole moment induced in a spherical particle

Consider a spherical metal particle made out of gold. If there is an external charge somewhere near the gold particle, is there a way to calculate the resulting dipole moment that is induced by the ...
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1answer
179 views

Dielectric modification of electrostatic equations?

I have learnt that in cases of electrostatic fields inside a dielectric of any source charge, the field is reduced by a factor of K( if K, the dielectric "constant", is taken everywhere to be same). ...
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1answer
247 views

Electrons drift velocity and capacitors

My friend said this to me and just want to make sure this is right " when we connect the a battery to a LED and the 2 poles are connected, electrons flow from the (-) to the (+) but with very low ...
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1answer
148 views

One terminal of an ideal voltage source connected to earth->Massive current will flow?

Assume we have a "somewhat" ideal voltage source like a DC power supply powered by mains. Take just one terminal and form a conductive path between it and earth ground. Assuming that no conductive ...
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1answer
173 views

Source of potential energy in a capacitor being pulled apart

When the plate spacing is large the capacitor system is storing more energy than when it is small. If one manually changes the spacing, where does the additional energy "come from" as the plate ...
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4answers
123 views

Capacitors' working in a circuit

Does charge in a capacitor containing circuit stop flowing when the potential of the capacitor becomes equal to the potential of the battery??
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1answer
693 views

Energy Change in a Capacitor by Inserting Dielectric

This is a practice Physics Subject GRE problem. A parallel-plate capacitor has plate separation $d$. The space between the plates is empty. A battery supplying voltage $V_0$ is connected across ...
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4answers
4k views

Potential Difference Between Capacitors in Series

I am struggling to find an answer to this, hopefully relatively simple, question. I had a search on stackexchange but couldn't find anything helpful. We are learning about capacitors in Physics and I ...
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2answers
712 views

Equivalent RC circuit to a RRC circuit?

I'm in doubt about a situation that I've seen sometimes: imagine we have a resistor in parallel with a resistor and a capacitor in series. Since I don't know how to generate figures of circuits to ...
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1answer
321 views

Capacitance of a conducting disk

I'm reading this(PDF) derivation of the capacitance of a thin conducting disk. The surface charge density of such a disk can be shown to be: $\sigma(r) = \frac{Q}{4\pi a\sqrt{a^2 - r^2}}$ (in ...
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4answers
4k views

Capacitor Charging and Discharging when connected to the ground

When we charge a capacitor using a battery and then remove the battery, the plates of capacitor becomes charged. One holds positive charge and the other one gets equal negative charge. o. k. ? Now ...
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0answers
64 views

Capacitors discharging in series [duplicate]

If you connect positive plate of a charged capacitor to ground, it doesn't get discharged. Now consider $4$ capacitors of equal capacitance connected in series to a $10\, \mathrm{V}$ battery. Connect ...
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1answer
878 views

How we approach RLC circult from RLGC model?

In the text, it introduces a practical model to investigate a transmission line (like BNC cable), it considers the transmission line has resistive $R$, inductance $L$, conductance $G$ and capacitance ...
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1answer
495 views

Finding the Steady State Charges

Here the problem states to find the steady state charges on the condensers.<<<< According to me the charges on second at steady must be ...
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1answer
40 views

Work due to introducing a dieletric in a capacitor

I have a doubt about a couple of exercises tha asks to find the work done on introducing a dieletric between the plates of a capacitor. Yes, this question is in the general case, how do we procede? I ...
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2answers
5k views

Inserting metal into parallel plate capacitor

The plates of an isolated parallel plate capacitor with a capacitance C carry a charge Q. The plate separation is d. Initially, the space between the plates contains only air. Then, an ...
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2answers
189 views

Flashlights and Capacitors

Why capacitors are used in flashlights of cameras instead of attaching the light directly to the battery? How this leads more light?
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4answers
564 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 ...
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3answers
8k 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 ...
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1answer
304 views

Potential of a conductor depends on the size and shape of the conductor. How?

1) When a charge 'q' is given to an isolated conductor, its potential will change. 2) The change in potential depends on the size and shape of the conductor. I could understand the point no. 1. ...
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3answers
110 views

Where are exactly the charges of charged capacitor?

If a capacitor is connected to a battery and is charged, are there charges inside the wires or do they just accumulate on the surfaces of capacitor?
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2answers
205 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 ...
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3answers
673 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. ...
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1k views

Why does a capacitor discharge?

Suppose a charged capacitor (parallel plates), the negative and positive charges on two plates attract each other. Which force cause the negative charge carriers (electrons) move through the circuit ...
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1answer
922 views

Calculate Capacitance in Series AC Circuits?

I'm supposed to calculate the capacitance of an unknown capacitor in series, but I'm not sure exactly which equation to use. I know the voltage across the resistor (Vr), voltage across the capacitor ...
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1answer
762 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 ...
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1answer
463 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 ...
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1answer
1k views

Two capacitors sharing charge

My two capacitors:                               I have these two capacitors ($C_1 = 3\mu F, C_2 = 4\mu F$) both initially under 19 volts. Then, I added a dielectric with $k=4$ at $C_1$ and entire ...
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1answer
83 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 ...
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4answers
312 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 ...
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1answer
579 views

Capacitor and hydraulic analogy

Would anyone kindly explain me the hydraulic analogy for the working of a capacitor w.r.t the article of wikipedia http://en.wikipedia.org/wiki/Capacitor... Help!!
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1answer
2k views

What do physical properties of materials trigger the capacitive touch screen?

I have watched some youtube videos about capacitive touch screen http://www.youtube.com/watch?v=ZHzaVzYEZbw http://www.youtube.com/watch?v=GmCE18RMEeQ The videos show that a conductor(finger), in ...
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3answers
9k views

Capacitor circuits with light bulb

Let's say we have a normal circuit with a light bulb, with wires and a battery. When one places a capacitor in this circuit, how is the light bulb able to light up, even when the capacitor prevents ...
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2answers
9k views

What happens to capacitor’s charge when the plates are moved further apart?

In my physics textbook there is an example of using capacitor switches in computer keyboard: Pressing the key pushes two capacitor plates closer together, increasing their capacitance. A larger ...
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1answer
2k views

How would I explain a farad being a second per ohm?

The farad has many alternative representations in SI. I can comprehend some of them. For example, a capacitance of 1 farad means that it will take a single coulomb to create a single volt between the ...
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1answer
122 views

Why does the presence of a battery change whether a circuit is in parallel or series?

If I take a closed circuit with two capacitors and a voltage difference, the circuit is apparently in parallel, but if I introduce a battery, the circuit is in series. Why does the presence of the ...
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3answers
672 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 ...
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2answers
2k views

How does the voltage between two charged sheets change if change their distance

Suppose I have two charged capacitor plates that both are isolated and carry a charge density $D = \frac QA$. According to textbook physics the electric field between them is given by $E=\frac D ...
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2k 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 ...
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3answers
2k views

What's the difference between Capacitors, Ultra-Capacitors and Batteries

Capacitors are known to hold and release energy very quickly, unlike the slower release that batteries exhibit. If one were to bunch many (1000's of) capacitors together could they function as a ...
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0answers
22 views

How are current and voltage out of phase in capacitive circuit? [duplicate]

Possible Duplicate: Physical explanation for capacitive circuit We say that in capacitive circuit, the voltage and current are out of phase. Current is 90 (degrees) ahead of voltage. What ...
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1answer
107 views

Magnetic force on capacitor

I have this problem: I have a capacitor formed by two parallel square-shaped plates, of side $a$, and with distance $d$ between them. They're asking me out of other things, the magnetic force as a ...
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1answer
211 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?
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1answer
9k 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 ...
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1answer
3k 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 ...
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2answers
449 views

Explanation of NMOS processes

Gate (poly-Si + $SiO_2$) and $p^{-}$ silicon operate as capacitors. But how are voltages and charges applied? In order for inversion to occur, there should be charges formed in poly-Si, right? How ...