Questions tagged [capacitance]

The ability of an object to store electric charge.

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1answer
713 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 ...
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656 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 ...
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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 ...
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3k views

Breakdown voltage of a dielectric

I know that a capacitor with a dielectric can operate normally up till a certain voltage (AFAIK called breakdown voltage) which depends on the strength of the dielectric placed between the plates. ...
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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 between $...
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Capacitance of Non-concentric Spheres

We all know how to obtain the capacitance $C=\frac{ab}{b-a}$ (ignoring constants) for two concentric spheres of radii $a,b$. I was just thinking to myself, what would happen to the capacitance for ...
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4answers
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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 ...
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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 ...
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4answers
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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 ...
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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 ...
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2answers
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RC circuit theory and voltage in the capacitor vs Ohm's Law

Consider a simple series RC circuit at steady state (capacitor is full). I've been told that once the capacitor is full we can literally "cut" the circuit because no current can flow. That ...
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1answer
762 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 ...
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1answer
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Why is this charge distribution in correct? Capacitors in parallel and series

Please consider the circuit diagram below, in particular, look at the capacitors enclosed by the green loop. *Note that the green loop and the (+) and (-) charges on the plates were drawn by me, the ...
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Potential difference between conductors

Reading some books there is something that i don't understand. Is the capacitors topics when they name a potential difference between conductors. As i know, Potential difference is the difference in ...
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Is it true that capacitors closer to a power source charges quicker and gets priority?

Let's say I hook two capacitor in a parallel circuit with a voltage source. Would the capacitor closer to the battery be charged up first? Because when the voltage excites and draws electrons from the ...
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1answer
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Calculating capacitance of arbitrary plate shape and arrangement.

Looking for suggestions on how to approach calculating the capacitance of a capacitor where the plates have an arbitrary shape. I've seen derivations of capacitance for a few highly symmetric ...
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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?
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3answers
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Why do charges enter the capacitor in the first place?

I have been studying Capacitors for the past year now and the one thing I don't understand is how a charge is stored on the capacitor. Essentially, a circuit with a capacitor is an incomplete circuit ...
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1answer
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How to calculate the charge and the potential across a charged capacitor charging an uncharged capacitor?

Initially, there is a single capacitor $A$ attached to a power source that charges it to a certain voltage $V$. Once it is charged, it is instantaneously removed and placed in a circuit with an ...
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1answer
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RC Circuit , Calculate Time Constant

Given this diagram: With S1 switch closed and S2 switch left open, I am trying to find the time constant Relevant equations I know τ = RC for a basic circuit, but how would you calculate it for a ...
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1answer
2k views

How do home-made capacitator bottles affect a tesla coil?

In the tutorial I'm following, the guy uses 6 snapple bottles to make capaciter (by covering them with foil and filling them with salt water) for a 9kV 30mA input. I have a stronger transformer (15kV ...
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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 ...
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1answer
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Calculating Systematic Error for capacitor charge time constat

I need to calculate systematic error for $\tau$ in capacitor's charging formula( $V_c(t)=V_s(1-e^{-t\over\tau})$ ) I converted it to : $\tau=-{t \over ln(1-{V_c \over V_s})}$ and continued by doing: $...
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Can hair be used as an dielectric?

I was letting my mind freewheel, and it occurred to me that hair, containing keratin, is a polymer. It is also capable of acquiring and maintaining a charge as happens, on occasion, when brushed. So ....
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Capacitance of two cocentric spheres, contradicting results

Suppose we are given two conducting, cocentric spheres of radius $a_1$ and $a_2$ respectively. The inner sphere with charge $q$, the outer sphere with charge $-q$. I can calculate the capacitance of ...

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