Capacitance Definition and 874 Threads

Homework Statement Capacitor C1 is charged so that potential difference between its plates is 20 V. Another capacitor C2=33µF has potential difference of 4 V between its plates. After plates of the capacitors that carry the charge of opposite sign were connected the potential difference became...

Homework Statement After the switches have been closed, in which circuit will the charge on the left hand capacitor increase? decrease? stay the same? Picture: [PLAIN]http://img714.imageshack.us/img714/3369/capacitance.png Homework Equations (1/Ceq) = (1/c1) + (1/c2) q = cv...

Homework Statement The equivalent capacitance of the capacitors shown in the figure is 9.23 MicroF Homework Equations http://upload.wikimedia.org/math/2/f/5/2f5b978fd081ea63e204909addf3d028.png http://upload.wikimedia.org/math/f/a/3/fa34ce461e6988fd973081401cc9790c.png The...

Homework Statement The equivalent capacitance of the capacitors shown in the figure is 9.26 uF http://session.masteringphysics.com/problemAsset/1122585/1/Walker.21.58.jpg Homework Equations Cseries = 1/Cs = 1/c1 + 1/c2 + ... Cparallel = Cp = C1 + C2 + ... The Attempt at a...

Homework Statement Hi again! I've been handed an assignment in which we are to find the capacitance of a variable capacitor consisting of seven semicircular plates with a radius of 2 cm spaced 1 mm from each other. Every other plate is connected to a common +terminal, and every other to a...

Homework Statement Hi, I have virtually no background in electronics and I have been given the following task. I have to measure the capacitance of the (real) circuit below (using labview, but it is the theory of how to do this that I am interested in). I am not able to use the...

Hi again! I got stuck in this question (Pic), the original question is the fig. 1. I then arranged the charges on the plates (fig 2) and then separated the plates to form three capacitors. Now I just don’t know what the capacitance will be and how to find it! First I thought to ignore the...

Hi all, This question was given in my physics book. Given that: C1 = 4uF and C2 = 6uF (u=micro) ... it comes out to be C1 + C2 = 10uF I used the general method ... you know ... assign charges, assume potentials... solve equations. My question is that aren't the two capacitors...

Hello, I need to construct an AM radio's RC circuit that: 1. resonates to frequency f= 580 Hz 2. has a maximum current of I = 0.2 A 3. the capacitor has a maximum potential energy U = 2 x 10^-5 I need to find: The inductance and capacitance (L & C) of this RC circuit. Please help...

Dear all, I'm having some trouble calculating the capacitance matrix, as outlined below. So first of all, the lecture notes I'm using use an integral equation method (method of moments) to determine the capacitance of two infinitely long and thin parallel strips in vacuum, at a distance d of...

Hello, I am new to this forum (and no physics expert). I apologize if this topic is in the wrong place, but I would really appreciate help on the abovementioned topic. I am investigating the effect of temperature on the capacitance of capacitors for a school project. Since C =...

Homework Statement Consider two long parallel and oppositely charged thick wires of radius d with their central axes separate by a distance D apart. Obtain an expression for the capacitance per unit length of this pair of wires Homework Equations \oint \vec{E}\cdot d\vec{a}...

Total Capacitance[SOLVED] Homework Statement how do i calculate the total capacitance of the image attached, as there is series and parallel capacitor in the same circuit The Attempt at a Solution i did try using 1/8uF + 8uF but then could not get the answer. can someone please...

Homework Statement A battery with emf = 2V is connected to a RC circuit with a 450Ω resistor and an unknown capacitor. After 3.8 milliseconds, the current is 2.2mA. (a) Find the time constant and the capacitance. (b) Now, 2.9 ms after the charging begins, find the current I, the charge...

How does exactly higher capacitance have "more bang for your buck"? Hi! I'm trying to really grasp the concept of capacitance. Whenever I see a description of the definition, C=Q/V, they always say either: "More charge stored per potential", or "more bang for your buck". I don't really...

Capacitance (Please Help!) Homework Statement The charge on a capacitor increases by 21 \mu(micro) C when the voltage across it increases from 99 V to 127 V. What is the capacitance of the capacitor?Homework Equations There is Q=cV, or C=Q/v. But there are 2 unknowns and no number for the...

Homework Statement The oscillator of a 96.9 MHz FM station has an inductance of 1.4 μH. What is the value of the capacitance? Homework Equations I haven't the slightest idea. I've looked through the section in my physics book and looked all over online and I can't find anything. The Attempt...

I need a very accurate capacitance meter with capabilities down to + .01 puff. Any reccomendations?

Homework Statement Hi, i was working on finding the equivalent capacitance, but I'm not sure if I'm doing it right This is the figure : http://i8.photobucket.com/albums/a8/ryu0919/physicsproblem2.jpg? Homework Equations Find the equivalent capacitance? The Attempt at a Solution...

Homework Statement All the capacitors have the same value. Need to find the capacitance between ab. Homework Equations The Attempt at a Solution

Upon calculating the electric field for a plate of charge, you arrive at: E = Q/Ae (Q the charge on the plate, A the area of the plate, e the permittivity of the dielectic) But then, isn't the total electric field between the plates twice this because of the equal but opposite charge on the...

Homework Statement The plates of a parallel plate capacitor measure 15cm x 15cm, and they are separated by 6cm. The capacitor is charged with a potential difference of 18V, then removed from the voltage source and kept isolated. A 15cm x 15cm x 3cm slab of dielectric material (k = 2.5) is...

Homework Statement What is the equivalent capacitance of the four capacitors in the figure below? Take C1 = 2.6 µF, C2 = 4.1 µF, C3 = 3.9 µF, and C4 = 1.1 µF. Homework Equations Cequiv of capacitor in series = (1/C1)+(1/C2)+(1/C3)+(1/C4) Then take the reciprocal of the answer. The...

Homework Statement http://yfrog.com/mrcapdg http://img819.imageshack.us/img819/1172/capd.th.gif Find equivalent capacitance answer is 4C/3 Homework Equations whatever is in parenthesis is subscript formula1: series: 1/C(eq)= 1/C(1) + 1/C(2) + 1/C(3) + ... formula2: parallel...

Hi, can anyone tell me how to measure the parasitic capacitance in a generator?

Hi, How can I measure the capacitance of a capacitor, using the following: a battery, a digital voltmeter (which records voltage as a function of time), a digital ammeter (which records current as a function of time), an industrial capacitor, two copper plates, and several...

Homework Statement The problem considers the diagram in the photo that I have attached. Apologies for the poor quality, but sketching it on my computer would have been even worse! a) Write down Kirchhoff's laws for the circuit and show that when the switch is closed, the charge on the...

Hi guys, Today was the second time in a textbook that they calculated capacitance using C = \frac{dQ}{dV}. In my electromagnetics book and any sources I find online they use C = \frac{Q}{V}. Can anyone help me understand why they can do it like this? This type of calculation was done to...

Homework Statement [PLAIN]http://img806.imageshack.us/img806/2373/compquesti.jpg The Attempt at a Solution dont know where to start... i know i have to use complex numbers... advice needed please!

Can you tell me if I'm right with this. If you charge ten 1F capacitors in series at 10 volts. Each capacitor has a voltage of 1 volt and a charged capacitance of 0.1F. So if you discharged the ten capacitors in parallel the output would be equal to 1F of capacitance charge and 1 volt. or would...

Does anyone know how to calculate the capacitance of a metal strip of width 2a and infinitesimal thickness? The length of the metal strip is much larger than its width. Thanks a lot!

Homework Statement At time t=0, a cell of EMF E and internal resistance r is connected to the capacitor of Capacitance C. i) Derive an expression for the voltage across the capacitor at subsequent times. ii) If the capacitance is 5000uF and the voltage across the capacitor reaches 73 V...

Homework Statement This is not a problem from any book or any kind of source. I was just thinking on this. Suppose u have a capacitor attached to a battery. And then u insert the dielectric slab. Then do the electric field between the plates changes? Homework Equations The Attempt...

Homework Statement The capacitance of a water-filled parallel-plate capacitor with plate area 3.0×10^−3m^2 and separation 4.0×10^−2 mm is 0.66 uF 1.3 nF 53 nF 660 nFHomework Equations C=E_0A/d The Attempt at a Solution C=8.85*10^-12*3*10^-3/4*10^-5 C=6.64*10^-10 This is none of the...

this type of cable is used to transfer power underground: http://www.mahanson.com/images/Hendrix%20Cable.jpg see the drain wires? i would think that those would be a huge problem because they are grounded and are right next to the conductor, i suppose any shielding would have this problem...

NOT HOME WORK QUESTION! If a capacitor is attached to a battery, initially the separation between the capacitor plates is D then the distance is doubled(2D). The voltage should remain the same because it is still attached to a battery. C=E0A/D so the capacitance decrease by factor of 2. my...

Homework Statement A 100 μμF capacitor, C1, is charged to a potential difference of 50 Volts. The charging battery is disconnected and the capacitor is connected to a second uncharged capacitor, C2. If the potential across C1 drops to 35 volts, what is the capacitance of C2? Homework...

Homework Statement Consider four concentric spherical metal shells of radii r, 2r, 3r, and 4r. The middle two shells are connected by wire, as shown. What is the total capacitance of the system? In your solution, clearly explain your method. Homework Equations u= 1/2cv^2 The...

[b]1. ok, there are 2 capacitors in series in a DC network, with A having a capacitance of 1.6 nanofarads and B having 5 nanofarads capacitance, but how do i find the charge, voltage and energy stored in each if the supply voltage is 24 volts. if anyone could help within the day that would be...

Hallo, i'm trying to implement a comsol simulation of a impedance spectroscopy experiment. But unfortunatly I'm an absolut beginner in Comsol and i have many problems with this work. First of all i want to say that I'm using the AC/DC module, more precisely the transient analysis. At the...

i am having trouble with finding inductance and capacitance of a cylindrical shell with gap. say inner radius is a, outer radius is b, and filling dielectric between a and b, and its not a exact circle which have a small gap say d. its like a split ring but only one shell. How can i...

Capacitance using an axon.. :)? Homework Statement An axon membrane is 8.0×10-9 m thick. a) Find the dielectric constant of the membrane, if the capacitance C is 100 nF for an area A = 10.0 square mm. b) If the resting potential across the membrane is ΔV = - 90 mV, what is the charge ±Q on...

1. For the circuit of Figure 1, VT = 100 V, R = 5000 Ω and C = 400 μF; switch S is closed at t = 0. a) Determine the instantaneous power absorbed by the capacitance. b) Obtain an expression for the instantaneous power dissipated in the resistance. c) Determine the voltage...

Homework Statement There are 2 concentric shells. The outer shell of radius a is given a charge, while inner shell of radius b is earthed. We need to find the capacitance of the system. Homework Equations Delta V = - integral E.dl (for some funny reason, latex is...

Homework Statement An airplane flies through a thundercloud and picks up an excess charge of 1 microcoulomb. When the plane comes into land, its wings form approximately a parallel plate capacitor with the ground. What is the capacitance of this system? What is the potential of the plane...

Homework Statement A capacitor stores 0.12 J energy when connected to 6 V voltage source. What is the capacitance of this capacitor? (UNIT:uF) I am just not sure how to go about answering this question. The formula for capacitance is C=(Q/V), but I am not sure how to incorporate energy...

Homework Statement Determine the capacitance of two conducting plates facing each other at an angle as shown (in link) . Plate A and B have dimensions of 10x20 cm and 10x (20sec30) (angles in degrees) Homework Equations C=( \epsilon A)/d The Attempt at a Solution not quite sure can...

Homework Statement In the attached question about total capacitance of the network, because of the layout I wasn't sure if this should be totalled as capacitors in parallel or capacitors in series. I was thinking perhaps parallel, but am not sure. Thank you! :smile: Homework...

Homework Statement A Purely resistive resistive 100w, 110v lamp is to be supplied by an a.c. source of 230v r.m.s at 50Hz. what value of pure capacitance could be put in series to adjust the current flow to a suitable value? Homework Equations p=iv q=cv v=ir i know a number of other...

Homework Statement When water is boilded under a pressure of 2 atm, the heat of vaporization is 2.2 x 10^6 J/kg and the boiling point is 120 degree C. At this pressure, 1 kg of water has a volume of 10^-3 cubic meter and 1 kg of steam has a volume of 0.824 cubic meter. a.) Compute the...