Solenoid Definition and 752 Threads

I know the magnetic field inside the solenoid is μIn/L and outside is 0 (provided that the point is near the solenoid). But if we had a long solenoid and choose a point far from the solenoid (and perpendicular to it), would it behave like a wire? Would the magnetic field be μI/2πR?

Homework Statement We're given two solenoids with identical currents and turns per unit length. But the solenoids have different diameters. Would a metal BB experience a larger acceleration in the smaller diameter tube, assuming we use the same BB in both solenoids it accelerates along the...

When we calculate magnetic field of iron core solenoid, should we multiply "relative permeability" or "effective permeability"? I thought that we should use relative permeability, but wiki(http://en.wikipedia.org/wiki/Solenoid) says that we should use effective permeability. I'm so...

Homework Statement A long solenoid with 1000 turns per meter and radius 2cm carries an oscillating current given by (5A)\sin(100\pi t). What is the electric field induced at radius r=1cm from the axis of the solenoid? What is the direction of this electric field when the current is...

Hello I have been doing some thinking related to Ampere law and behaviour of magnetic field inside materials of different permeability. In the process, I came up with the following thought experiment: Try imagining a very long solenoid with steady current I. Turns of the solenoid are...

If you have a solenoid positioned along the z axis... ...how would one find the b-field at slight deviations of x and y? I have been googling for hours and can't find anything other than the fact that it is very difficult! Thanks guys!

Homework Statement Suppose we have a toroidal solenoid with square cross section and whose axis of symmetry lies along the z axis. Suppose a current I(t)=kt runs through the solenoid. Find the induced electric field at an arbitrary point on the z axis. Homework Equations \oint \vec E \cdot...

I have to measure the magnetic field created by a solenoid. My attempt would be using a commercial Axial Hall Probe, or a Hall Sensor with some electronics. It has got an active (sensing) area with a diameter <1 mm. My coil is 12 mm long and has an inner diameter of 9 mm-s. My problem is that...

Hi all, I'm building a tennis ball launcher for my dogs, and was successful in building a spring loaded one with a "whacker bar" that rotated on a pin. A wiper motor turned the bar until the bar got to the half way point around the pivot, then the spring would pull the bar, hit the ball, and...

Instead of the usual B = μ0NI for field inside solenoid... how should i go about finding the field let say... 10cm away from one end of the solenoid 1. directly at the z-axis 2. not directly at the z-axis this is assuming the solenoid has finite length, finite number of turns ,finite...

Homework Statement A metal ring of radius r = 24 cm surrounds a solenoid of radius R = 2 cm and 10000 turns. The magnetic field inside the solenoid changes from 5 T to 3 T in 0.1 s. Find the magnitude of the non-Coulomb electric field along the ring. Answer in units of V/m Homework...

In a Faraday flashlight, a magnet is shaken to and fro in a solenoid to induce an EMF and thus current. Something like this: http://express.howstuffworks.com/gif/autopsy-flashlight-tube.jpg If the solenoid were to cover the entire length of the interior, and thus the magnet is only moving...

A solenoid of length 0.4 m and diameter 0.6 m consists of a single layer of 1000 turns of fine wire carrying a current of 5 x 10-3 A. Calculate the magnetic field strength on the axis at the middle and at the ends of the solenoid. I know the field inside a long solenoid, B = μNI, which is...

I am having some trouble understanding why and how the emf changes when a bar magnet is dropped into a solenoid. As the magnet moves down (have not entered the solenoid yet) it experences an increase in magnetic field. As it enters the magnet it experiences an increase in magnetic still until...

Homework Statement A 27.0-cm long solenoid 1.25 cm in diameter is to produce a field of 0.215 T at its center. How much current should the solenoid carry if it has 900 turns of the wire? Homework Equations B = μIN / l The Attempt at a Solution Why am I given the diameter plus the...

I need a review of solenoid equations, such as equations for bar solenoids, toroidal solenoids, and toroidal solenoids with an air gap within them. I think that somewhere along the line I may have learned something incorrect, so I would like to kill any douts that I have by ascertaining myself...

Some Background I am working on a soccer robotics project called RoboCup (perhaps people here have heard of it), which revolves around building a fleet of autonomous soccer robots that play against each other (league website - http://small-size.informatik.uni-bremen.de/ ). The kicking...

Homework Statement A 10 cm long, 1 cm diameter solenoid contains 500 turns of wire. A current that varies as I = 5Sin(100πt) Amps flows through the solenoid wire. Calculate the magnitude of the magnetic flux at the centre of the solenoid as a function of time using equation (1). Compare this...

I'm looking at this picture from part of an explanation of the torque on a coil of current arranged as a solenoid: http://www.physics.sjsu.edu/becker/physics51/images/28_30_Torgue_on_solenoid.jpg Now, they claim that the torque is directed into the page, but I can't understand why. I agree...

Hi my name is Juan Motta and i´m new in this forum, I`m a total begginer in physics. I´m planning to build a solenoid (air coil or iron coil, i don´t know) with different form, like this: http://www.divshare.com/img/thumb/19310413-b22.jpg And i have some cuestions about, because i...

Homework Statement A solenoid has a radius of 2mm and a length of 1.2cm. If the # of turns per unit length is 200 and the current is 12A, calculate the magnetic flux density at a) the center and b) the ends of the solenoid Homework Equations The biot-savart law: \vec{B} = \frac{\mu_0}{4...

This is more a theoretical question than a practical one. Basically I want to know if the formulas I arrive for the flux of a Toroid and a Solenoid are correct Leaving aside the integration part this is the basic formula for the flux \phi = BNA B = magnetic field N = number of turns of...

I have heard that when a magnet is moving completely inside a solenoid, there will be no induced emf. Is that true ? Personally, I think even the magnet is moving inside a solenoid with speed v, there will still be induced emf. Assume a magnet is moving inside a solenoid from left to right...

Homework Statement A solenoid of length 20.0 cm is made of 5000 circular coils. It carries a steady current of 10.0 A. Near its center is places a very flat and small coil with a resistance of 2.50 Ω made of 100 circular loops, each with a radius of 3.00 mm. This small coil is oriented so that...

Homework Statement A square loop with side-length a is positioned at the centre of a long thin solenoid, which has radius r (with r>a), length l and N turns. The plane of the loop is perpendicular to the axis of the solenoid, find V_{emf} induced in the solenoid Homework Equations...

Hi all. I would like to do a finite element simulation of a coil in a time-varying magnetic field, to see how much current is induced in the coil, and also to see how the coil itself affects its surroundings. Now my question is, how do I model a coil with several thousand turns in a practical...

Homework Statement First, I will describe the solenoid referenced, as it is from another problem. The solenoid is made by winding a single layer of No. 14 copper wire on a cylindrical form 6cm in diameter. There are 5 turns per centimeter and the length of the solenoid is 30cm. Consulting...

When a magnet is pushed into a solenoid, the solenoid will have an induced emf and hence induced current since it is a closed circuit. But when the magnet is outside does, how does the magnetic field of the solenoid look like? I mean is it combined with the magnet's magnetic field or does it...

Homework Statement Attached file shows the problem statement. The Attempt at a Solution I can do this problem easily. Problem is that there's just one step in my book's derivation that I don't understand. It sets ρ equal to the hypotenuse in the triangle and then says that: dl = ρ/sinθ...

Hello everyone, I'm doing research on solenoid design for satellite magnetic torquers. I've come across a couple of papers that mention "Loney's Solenoid". Does anyone know who Loney is/was and where I can find the details on "Loney's Solenoid"? Thanks. This is my first post. Sorry in...

In Fig. 28.8, a view of the solenoid, showing the clockwise sense of the current in the windings, is given. An electron is in circular motion near the center of the solenoid, with an orbital diameter of 3.0 cm. The speed of the electron and the sense of the orbital motion are closest to The...

Hey, I'm wondering if a short solenoid (50mm) would be able to pull a 300mm core through it if it was open at both ends? Or would the soleniod stop acting once the core had come to the far side? I've attached a pic of what I'm trying to do (forgive the paint drawring). I'm basically trying...

Hi, I was browsing through many academic papers and could find little information of a simple solenoid with a permanent magnet in the core of the solenoid. Solving the field in a simple solenoid is very straight forward, but I was having difficulty understanding the interaction between the...

Hey guys! New guy here so bear with me on my first post:) I'm trying to calculate the B field in the center of a finite solenoid for different outer radius sizes. I was able to find a formula online that gave the B field in the center of a solenoid given its length, inner radius, outer...

Hello I want to calculate field of the Solenoid Coil with AC current. For a DC current field is calculated easily from the BiotSavart. What is the process for AC current? Get the L value with RLCMeter in operating frequency? Is there an equation to get the field with...

Homework Statement The mathematical formula that connects the magnetic field in a solenoid with the current is given by B=((μ0 x n)/(2πr)) i where μ0 = 4∏ x 10^-7 NA^-2 is the 'magnetic constant', n is the number of turns or loops of wire (unknown), r is the radius of the solenoid (0.023m)...

Hey, The question concerns a basic solenoid with an oscillating current, we have a loop inside with a particular resistance and we want to determine the current induced in this particular loop. The question is in the image below: Right, well it tells us to determine the electromotive...

I have a solenoid with 180 turns, which is 10 cm long. It has a half core of magnets (which could be constituted as part iron core). The magnetic field strength was measured to be 0.004982 T inside the solenoid around the middle when 12v was run through it and 0.004512 without power running...

Homework Statement I've been given a solenoid and I have N/l = 100 turns/meter, dI/dt = 0.05A/s and a radius of 0.005m. I am only concerned with the dI/dt. Homework Equations B = μ*N/l*I \Phi = \int\int B\bulletn dl \epsilon = d\Phi/dt The Attempt at a Solution For B I get the...

Homework Statement A simple loop of 5 cm radius encompasses the middle turns of a long coil. The coil has 2500-turns, is of length 1 m and radius 1 cm, and carries a current of 10 Amps. What is the magnetic flux through the single loop? Homework Equations B=μIN/L with L=1: B=μIN...

Hey guys, for my engineering course, we are build an autonomous watercraft with a self expanding debris recovery system. My job is the debris recovery system, and part of this system basically using a solenoid to expand the system. The idea is that a frame made of PVC piping, which will...

Homework Statement A solenoid is 0.16 m long and consists of 130 turns of wire. At its center, the solenoid produces a magnetic field with a strength of 2.0 mT. Find the current in the coil. Homework Equations B=μNI/L B=strengh of magnet N=number of loops I= current and L=lengh μ is...

Homework Statement A solenoid is wound with a single layer of copper wire of radius 0.24 cm. The solenoid is 1 cm in diameter and 2.6 cm long. What is the inductance of the solenoid per unit length? Assume that adjacent wires touch each other and that insulation thickness is negligible...

1. A current balance is constructed to measure the force between a solenoid with n=10000turns per length and a straight wire segment of length l=0.05m inside the solenoid and perpendicular to the field. The current through both the solenoid and wire segment is I=14A. What is the B field inside...

QUESTION: I have two solenoids, one connected to a power supply so that current flows through the coil, and the other connected to a galvanometer. When I disconnect the power supply in the left coil, current flows momentarily in the right coil. Explain why and predict which way the...

Homework Statement polarity of a horseshoe shaped solenoid given symbol for power source large line small line. Current flows through the right end of the horsehoe and out of the left end. The wire is wrapped in a CW direction if looking at the left end of the magnet. The wire is...

Homework Statement There are two coaxial solenoids, each 30cm long. One is inside the other. Each carry a current of 3A, but in opposite directions. Inner solenoid has a radius of 3cm and the outer has a radius of 6cm. Inner has 15 turns/cm and the outer has 30 turns/cm. Find the...

I was reading through an example question calculating the electric field in a solenoid and it made an assumption that the radial electric field must be equal to zero because there is no excess charge in the system. I don't understand when this is true or even why it is true, any suggestions...

A 30mH solenoid inductor is wound on a form 0.4 m in length and 0.1 m in diameter. A coil is tightly wound around the solenoid at its center. the coil resistance is 5.0 ohms. The mutual inductance of the coil and solenoid is 60μH. At a given instant, the current in the solenoid is 0.3A and is...

Homework Statement Connect a battery to a solenoid A cylindrical solenoid 40 cm long with a radius of 8 mm has 250 tightly-wound turns of wire uniformly distributed along its length (see the figure). Around the middle of the solenoid is a two-turn rectangular loop 3 cm by 2 cm made of...