Capacitance Definition and 874 Threads

Given that two spherical conductors of radii r1 and r2 are separated by x>>(both r), connected by a thin wire, and charged with 7 uC - how is the charge distributed between the spheres (no charge on wire)? I tried using charge density but: Qtot/A1+A2 = Q1/A1 + Q/A2 doesn't work by...

The variable capacitor in the tuner of an AM radio has capacitance of 1800pF when the radio is tuned to a station at 550 kHz. a) What must be the capacitance for a station at 1600 kHz? I found the frequency first and then am I supposed to setup the 1600 equal to the frequency to find the...

OK, let's say you have identical capacitors, and you charge one and do not charge the other. Then you connect the two. Will the energy in the two-capacitor system be the same as the energy in the first capacitor before it was connected?

http://img.photobucket.com/albums/v64/neik7/asg.jpg this is neither a parallel nor a series circuit i duno how to find the equivalent capacitance from a to b can anyone give me some hint ? :cry: thanks in advance

Small question: The capacitance of parrallel plates decreases as you increase the distance between them, why? I know the voltage increases, because the electric field is constant, but how does this stop more charge from entering the plate? I mean our voltage relative to some far-off charge is...

A capacitor is often used in electronics to keep energy flowing even if there is a momentary loss of power from the electric company. What capacitance would be required to a 150-watt televisiion (plugged into a standard 120 volt ac outlet) to protect it from a .1 second lapse in power? I...

the general definition of capacitance is that if you have an arrangement of two conductors, and you put a charge +Q on one and -Q on the other, and a potential difference of V results between them, the capacitance is Q/V. But what if the charges on each conductor don't have the same magnitude...

Hi Guys, Here is a question that I cannot get my mind on. Bad day I guess. I'm trying to figure out the answer. Here comes the question: How far away from each other would two metal plates, 2 square meters in area each, have to be in order to create a capacitance of 1 micro Farad...

I've done a search for some help on my problem, but I haven't seen anything resemble it. Anyway my question is the following: Not all dielectrics that separate the plates of a capacitor are rigid. For example, the membrane of a nerve axon is a bilipid layer that has a finite compressibility...

How can I show that the capacitance of a plate capacitor increases if a dielectric material fills the space between the plates?

Here is the question A(n) 2.00 µF capacitor is charged to 520 V and a 4.60 µF capacitor is charged to 570 V What is the voltage for each capacitor if plates of opposite signs are connected? Any help would be helpful. I have bene trying to get this and haven't been able to all night. I...

A parallel plate capacitor has charge Q and plates of area A. What force acts on one plate to attract it toward the other plate? It's F = Q^2 / (2*8.854e-12*A) ... something to do with the electric field divided in 2? Wondering why there's a 2 in the denominator... thanks :)

Hi, I have a problem about the capacitance of two cylinders eccentrically located one inside the other - with radii a and b resp., their centers have a distance c apart. I've tried that with the method of images, considering the eqipotential "cylinders" of a system of two infinite parallel...

The electric field between the plates of a paper-separated (K=3.75) capacitor is 9.41E4 V/m. The plates are 1.75mm apart and the charge on each plate is 0.775E-6C. Determine the capacitance of the capacitor and the area of each plate? I got the voltage by V=Ed. and that came out to 164.675...

I just need a hint on this. 2 plates of a capacitor hold +1500 C and -1500 C of charge, respectively, when the potential difference is 300 V. What is the capacitance? I know I have to use c=Q/V, but which charge do I use the positive or negative?

if we introduce a conductor b/w the plates of a capacitor then what will happen? will the capcitance increase or decrease?

Hi, I have learned that as a capacitor discharges it emits some kind of a wave. Plz tell me wether the frequency of this wave increases as the capcitance of this capacitor increases. Or please tell me is there a way to find out the cpacitance of a capacitor by looking at the wave that this...

Hi, I have read that as a capacitor discharges, it emits electromegnetic waves. Plz tell me does the frequency of these waves increase as the capacitance of the capacitor increases. Thanks a lot, Chamal.

2 problems. I was just wondering if someone can help me start off the problem. The rest, I'll try to do because I don't know how to setup the problem. 55) A virus rests on the bottom plate of oppositely charged parallel plates in the vacuum chamber of an electron microscope. The electric...

A capacitor, in a series with a 720 ohm resistor, is being charged. At the end of 10 ms its charge is half the final value. The capacitance is about: a)9.6 uF b)14 uF c)20 uF d)7.2 uF e)10F Now how in the heck and I suppose to know this one. I know ohms law and I know how to find...

Hello, We haven't covered capacitance in class yet, but our lab involves the use of capacitors, so I thought I'd throw out a general question. We were asked to use the MOS FET Electrometer to measure charge, and we were given the formula: Q = CV Where C is the capacitance, and V is...

How is... Capacitance, Resistance and Time to fully charge related?

without revealing any sort of base info such as current, voltage or charge

[SOLVED] Capacitance potential Hello, I have 2 questions here to ask for help with? 1) a .2F cap is desired. What area must the pplates have if they are to be separated by a 2.2mm air gap? My formula i used with substition was C=e_o (A/d) with e_o = 8.85x10^-12. I rounded my...