Coil Definition and 864 Threads

Homework Statement This is a question about turning effect on a current-carrying coil lying between the poles of a magnet. Please refer to the following link: http://img11.picsplace.to/img.php?file=img10/22/N1_000.gif On the textbook, it is stated the turning effect on the coil can be...

I was wondering what the energy density of superconducting coil/tape is. I essentially what to be able to say is for every centimeter or inch of this material this is the amount of energy could be in it (kW, kWh, etc). So the background; I would like for the parameters to be for...

Homework Statement Two coils have the same number of circular turns and carry the same current. Each rotates in a magnetic field in a setup similar to the square coil in the figure below. Coil 1 has a radius of 4.2 cm and rotates in a 0.19 T field. Coil 2 rotates in a 0.42 T field. Each coil...

Hello All, I did an experiment recently involving two coils in series with a high frequency signal running through them. My goal was to determine at what frequency the signal in one coil would be phase shifted by 90 degrees with respect to the first coil. I was able to experimentally...

Hello All, My question concerns induced emf in an air-core toroid setup. This is simply a thought experiment and I think I know the answer to this but thought I would run it past you all anyway. Picture a non-magnetic toroidal core with two one-layer coils wound on it 180 degrees apart...

Can i get some help with this homework problem?? A physicist wraps a long copper wire around a toilet paper roll and places the roll in a uniform magnetic field. The axis of the roll is aligned with the field. The radius of the roll is r = 6 cm and the strength of the field is B = 0.1 T. If the...

I have a homework problem where there is a long copper wire around a toilet paper roll that is placed in a uniform magnetic field. The axis of the roll is aligned with the field. I am given the radius of the roll, strength of the field, and a velocity at which the wire is unrolled. How do i...

Please help me if you can... question: Use the following quantities to calculate the magnetic field strength of the horseshoe magnet. Mass of coil: 20 grams current in coil: 2.0 amps length of bottom of coil: 10cm angle coil makes with vertical: 30 degrees Hint: Equate magnetic...

In a physics laboratory experiment, a coil with 210 turns enclosing an area of 12.7 cm^2 is rotated during the time interval 3.70 \cdot 10^{−2} sfrom a position in which its plane is perpendicular to Earth's magnetic field to one in which its plane is parallel to the field. The magnitude of...

An electric heating coil is immersed in 4.2 kg of water at 22°C. The coil, which has a resistance of 260 Ω, warms the water to 33°C in 3.5 mins. What is the potential difference at which the coil operates? I was looking through the chapter, and did not see any equations that I can use that...

Hey Everyone, I recently got a hold of a coupe of toroidal cores that I want to wind some wire on (see pic). They are roughly 2.5" OD, 1" ID, 1" thk. I plan to wind two coils of 20 gauge magnet wire onto them but I was wondering if anyone here knows how the factory-made ones are wound? Do...

Hi, I'm working on making a coil and I was wondering if there are some nifty equations out there to predict how much power the coils can make under a changing magnetic field of X gauss. I am going to be using 1 inch of a 3/8" x 2.25" bolt to wind my coil onto and I will be exposing it to a...

Hi, I'm working on making a coil and I was wondering if there are some nifty equations out there to predict how much power the coils can make under a changing magnetic field of X gauss. I am going to be using 1 inch of a 3/8" x 2.25" bolt to wind my coil onto and I will be exposing it to a...

"The magnetic field at the center of a 50-turn coil of radius 15 cm is 0.60mT. find the current in the coil." N=50, r = .15m, B = 6.0 * 10^-4 T, magnetic permeability = 4 * pi * 10^-7. B = (mag.per. * N * I)/ L However, I don't have L, which is the length. I do have r, the radius, but it's...

Hi all, Does anyone know about the working range and market availability of the induction coil sensors? The field that I am dealing with is in the range of 2000-5000 Gauss and it's not suitable to use a Hall-Effect Sensor. Thanks, Mike

Hi Everyone, I read the Tesla patent about bifilar pancake coils here: http://www.magnetricity.com/NeoG/Bifilar.php and I read about how they are supposed to decrease the impedance and increase the capacitance of the coil. So I constructed one to try out the idea. To my surprise, when I...

Hello All, I have been playing around with this digital oscilloscope and function generator that I am using at school. I first connected the function generator directly to the oscilloscope to get the hang of adjusting it, then I took a small coil I had laying around and connected it in...

Hi all, I'm new to this forum and I'm not a physicist. I'm a Cabinet Maker looking for a career change. I performed an advanced search on the entire site and was surprised to find not a mention in regards to Halbach Array. My understanding is that the special arrangement of nib magnets can...

Hello, I've learned from my study of oscillator circuits that an inductor has some inherent capacitance in it due to the distance between the individual windings. I've heard somewhere that if you place a permanent magnet close to a coil that it will behave like a capacitor and I was wondering...

Is there any expression for finding out the magnetic field due to an elliptical coil? Can we proceed with Biot Savart's law? If so what is the final expression?

I don't know how to answer these questions. :( I know the alternating current makes the magnetic field changes. And the changing magnetic field generates emf.But I don't know why the emf is large enough to push the aluminum ring upward, and how come it goes up? thx a lot.

A magnetic field with the time dependence shown in Figure 23-38 is at right angles to a 181 turn circular coil with a diameter of 3.91 cm. What is the induced emf in the coil at each of the following times? (a) t = 2.50 ms 0 V (b) t = 7.50 ms (c) t = 15.0 ms...

I was wondering about the following problem: You are looking down on a single coil in a constant magnetic field B = 0.9 T which points directly into of the screen. The dimensions of the coil go from a = 6 cm and b = 15 cm, to a* = 20 cm and b* = 19 cm in t=0.028 seconds. If the coil has...

What would be the change of the induced emf in the secondary coil of a two coil system ( without ferromagnetic core ) if both the amplitude and the frequency of the current in the primary coil would double?: emf would stay the same emf would be halved emf would be 4 times larger...

Hello, I am new here. I was hoping to get some help with a problem. I need to find the Induced Voltage in a coil in terms of the number of coils N, the length l, and time t. I think when all said and done the equation should look close to: NlcB[SIZE="1"]0*sqrt(1-cos(kl)), which is the...

Hello everyone, I'm confused on how to do this problem, it says: An electric generator contains a coil of 120 turns of wire formed into a rectangular loop 40.0 cm by 20.0 cm, placed entirely in a uniform magnetic field with magnitude B = 3.50 T and with B initially perpendicular to the coil's...

Does the formula tan (phi) = (wL - 1/wC)/R work without a capacitor? Can I turn it into tan (phi) = wL/R instead? I don't know what formula to use to find the inductance of an inductor in this question: A voltage source V = 160V sin (100t) is connected in series with an inductor and a 17.0...

Hey! Im 16 and love physics, but I am starting to get board with the regular school course and want to start a little project of my own, i thaught a coil gun would be a good start:biggrin: . Any way, I've looked on google on how to make one but all the instructions suck so i was wondering if...

Hi, My Question: What is the inductance of a coil if the coil produces an emf of 2.50V when the current in it changes form -28.0 mA to 31.0 mA in 12.0 ms? For this I know I will need to use this equation: E=-M(delta I)/(delta t) My problem is that I was wondering if coming up...

A coil is to be used as an immersion heater for boiling water. The coil is to operate at a voltage of V and is to heat an amount of water with a volume of v by T degrees C in a time interval of t seconds. Use 4190 for the specific heat capacity of water and 1000 for the density of water. How...

Hi again. I'm going crazy over this question. Does a longitudinal wave in a spring depend on the maximum speed of each coil? Me, I've always thought that the transverse velocity of the Particle or coil remains constant and independent of the wave speed itself. Am I wrong? Or did I misunderstand...

My school district requires that each high school senior complete what's called a "Graduation Project," in which the student makes a project of their choice that relates to their academics. There's no specific requirements about the actual project, just the completion of different components...

Alright there is a problem I was given and it has four parts, I got the first two but am having trouble with the last two. A)Consider a circular current loop of radius 10.5 cm with 200 total turns. Assume that the current through the coil is I. What is the magnitude of the magnetic field at...

i am looking for an equation (integral) , so that i can predict what width to make a coil of wire , of certain length ,and thickness, so that it comes out to an outer diameter of 1.5" with an inner diameter of .5".. i usually spend my time in the engineering section , but i thought that i would...

Let we have a piece of wire, copper, for example. Let we have the generator of alternating current with changing frequency. We connect the ends of a wire to clips of generator of an alternating current and then turn it “ON”. Resistance of a piece of wire does not depend on frequency of a...

Good day everyone, I was wondering how would you determine the magnetic field within a square coil? My colleague and I are trying to write a lab up on tangent galvanometers, but all we can find are models with circular coils, and ours is square. Any help is appreciated.

I thought people helped on this forum? If anything is unclear just ask, I'm checking for posts every minute. Come on people I have to get this done by 5 pm. I've gotten a little further. I believe it has something to do with mutual inductance. A metal ring (no current) is brought close to a...

I'm trying to track down a quantitative proof that the most uniform magnetic field between two Helmholtz coils occurs for a separation equal to their radii. So far I've just been playing around with the Biot-Savart law and proving that B is identical at several trial points along the axis...

Just a quick question about finding the magnetic induction field B on the axis of a circular coil shown on page 7 on http://www.physics.gla.ac.uk/~dland/ELMAG305/Elmag305txt5.pdf I understand why the field must be along the x-axis but why does (dlxr )x become dlrsin(alpha)? alpha doesn't seem...

The coil of a generator has a radius of 0.14 m. When this coil is unwound, the wire from which it is made has a length of 5.7 m. The magnetic field of the generator is 0.20 T, and the coil rotates at an angular speed of 25 rad/s. What is the peak emf of this generator? Please help me get...

I'm stuck on the following problem: A long thin coil of length l, cross-sectional area S, and n turns per unit length carries a current I. It is placed along the axis of a large circular ring of radius a, which is carrying a current I'. If d is the displacement of the center of the coil from...

This is the problem taken from Giancoli Chapter 20, number 80: The magnetic field B at the center of a circular coil of wire carrying a current I is : B = \frac{\mu_{0}NI}{2r} , where N is the number of loops in the coil and r is its radius. Suppose that an electromagnet uses a coil 1.2m in...

Howdy I'm having a ton of trouble with this question Basically I have a spiral coil running around the z-axis with radius 'a' height '2b' and pitch 'c'. The point (x,y,z) = (a,0,0) is on the spiral and n = 2b/c (that's the number of turns on the spiral). There's a steady current running...

I have my question,solution and the problem I faced in the attachment that followed.Thanks for anybody that spend some time on this question.

This is another question that I have think for very long hours but still find the solution to this question.I have my question in the attachment that followed.

i have think very long on this question but still can't figure out what is meant by the question.I have my question and my doubt on the attachment that followed.

Hi. I'm trying to find information about the circuit which controls raytracing within a television CRT tube (the circuit which controls the current through the steering coils deflecting the beam up down left and right)... How is this precise raytracing accomplished... what type of circuit is...

hey everyone. physics doesn't make sense to me. i need help (!) esp. since I am considering choosing it on highlevel in the IB Diploma programme I am in right now. anyway. so i have to answer this question for the class on wednesday, but I am totally lost. i would appreciate it a lot if...

A closely wound, retangular coil of 80 turns has dimensions of .25m x .4 m. The plane of the coil is rotated, in .06 sec from a position where it makes an angle of 37 degrees with a magnetic field of 1.1T to a position perpendicular to the field. What is the average emf induced in the coil...

I was told that P.d. supplied to the primary coil is used to overcome the back e.m.f. so that the the flux will keep changing, why is it so? What happened if the P.d. supplied is different to the back e.m.f.? Thx!