Electromagnetic induction Definition and 240 Threads

Homework Statement http://dc10.arabsh.com/i/03594/qn9gr42q192z.png What is the direction of current in ring 2 if : a) ring 2 moves towards ring 1 b) ring 2 moves away ring 1 The Attempt at a Solution I used Fleming right hand rule but I'm not sure if it is true, a) the...

Homework Statement When we place a magnet in a long coil of wire the emf will be maximum when the magnet is at either end. What would happen when the magnet lies in the middle of the coil (i.e: the same amount of flux is interacting with the coil at all times). Would we have an induced EMF...

Can someone please tell me why the magnetic field makes the electrons flow round the coil in a generator? Does the force of the magnetic field have to go in the same direction as the coil?

consider first , an induction motor... a rotating magnetic field is applied to an electrically conductive rotor, and the eddy currents induced will oppose the change in magnetic field experienced by the rotor, hence the rotor gets torque in an induction motor the rotating magnetic field is...

Fig.35 shows a light and flexible conducting loop X freely hung on a smooth horizontal rail. A bar magnet PQ approaches the loop from the right. Which one of the following descriptions about this process is correct? A If P is a N-pole, the loop will be repelled to the left and its area...

Hi everyone, So I feel sort of stupid posting what you'll probably find is a very elementary question but physics really isn't my best subject and I'm completely stumped. Thanks so much! Oh, and there's also the possibility that this question is just really badly worded. Homework Statement...

Suppose a single wire (in a horizontal position) falls toward a pole of a magnet. Does the wire slow down? A diagram is attached.

Ok, so my class has spent about a day on the topic of electromagnetic induction and I really you help on this subject because tomorrow i have a quiz. I don't need you to explain it in a super detailed way but in a fashion where the teacher will realize that i actually understand these topics...

we have studied electromagnetic induction that takes place in coils, solenoids, or wires forming geometrical shape, but my question is can electromagnetic induction occur in a single straight wire by changing B the magnetic field that crosses the wire? would there be electromagnetic flux and...

Homework Statement I have a few homework questions that ask for the direction of induced current for ex a loop of wire. I can't figure out how to find it .

I was thinking at electromagnetic induction in two parallel wires...I searched some websites about this and i found out that acording to Lenz's law :"An induced current is always in such a direction as to oppose the motion or change causing it". Acording to this an induced current is opposig the...

I'm not a physicist, in fact, I have absolutely no training in any related fields what so ever. I didn't even go to College. But in High School, some German guys came and took me out of class and gave me an IQ test, the results of which I was not allowed to know. However, I've come to invent...

Homework Statement A flat circular coil with 139 turns, a radius of 5.74 x 10-2 m, and a resistance of 0.502 Ω is exposed to an external magnetic field that is directed perpendicular to the plane of the coil. The magnitude of the external magnetic field is changing at a rate of ΔB/Δt =...

Hi, I been practicing for my physics compettiotion as I stumbled upon a difficult problem.I couldn't do I for days so I turned to internet in hope someone can help me. The idea is as following: You have a frame made of wire and its area is S it rotates with a angular speed of W, in a magnetic...

Homework Statement There is a circular loop in the horizontal plane and a bar magnet (with its north pole downwards) Is falling down along the axis of the loop... Now is the acceleration of the bar magnet less than,greater than or equal to g? Homework Equations The Attempt at a...

Homework Statement A circular loop with resistance 0.5 \Omega per meter of length is placed in a homogeneous magnetic field of induction B=2 Teslas. The magnetic field is perpendicular with the surface of the loop, as shown in the picture (image1). The radius of the loop is increasing...

Homework Statement Two infinite parallel wires, having the cross sectional area 'a' and resistivity 'k' are connected at a junction point 'P'. A slide wire of negligible resistance and having mass 'm5 and length l can slide between the parallel wires, without any frictional resistance. If...

a conducting rod of length 1 m is rotated with an angular frequency of 400/s about an axis normal to the rod passing through one of its ends .the other end of the rod is in contact with a circular metallic ring. a constant magnetc field of 0.5T parallel to the axis exists in the region.find the...

Hi there, I'm currently working on a personal project, not really a homework question and didn't get an answer there so trying this forum. The idea is for a device that harnesses vertical motion via electromagnetic induction for the purpose of energy harvesting. I have built a prototype to...

Homework Statement http://img269.imageshack.us/img269/8792/screenshot20100816at003.png Uploaded with ImageShack.us Homework Equations The Attempt at a Solution The answer says that the loop will reduce in area to minimize the flux linkage, but why? using Fleming's left hand...

When a charge is in motion, it produces a magnetic field. If the charge is in an external magnetic field, a magnetic force is induced on the charge. This I understand. When a conductor is moving relative to a magnetic field, there is an induced current in the conductor. This I don't get. If...

How is magnetic flux different from magnetic field? Or rather how are they related to each other ? My thought is say there is a magnetic field acting along the x-axis direction, a conductor is allowed to fall through the magnectic field and now there is a change in magnetic field, hence...

I understand what electromagnetic induction is and its applications. However, I don't understand why this occurs- is there an explanation for why a changing magnetic flux induces an electric current? Thanks

Hey, I have one question about the eddy current brake, or electromagnetic induction at all. For instance, slowing a roller coaster from let me say 40m/s to 10m/s in 20m by a eddy current brake(THIS IS NO HOMEWORK!). What is about the conservation of energy in this case. can you say that E kin +...

Homework Statement The problem can be found http://www.drewett-gray.co.uk/alevel/ff&e/papers/ffe_04_Jun.pdf" (page 10 and 11) Question 4 part B i and ii Mark Scheme if needed http://www.drewett-gray.co.uk/alevel/ff&e/papers/FFE_04_Jun_MS.pdf" Homework Equations Faradays law: The induced...

Hello. I am making a small induction motor and have been wondering about it's limits. I have googled a lot and can't find a helpful answer. Is there a maximum length of coil that a magnetic flux of specific strength can excite ? Thank you, Gary.

Homework Statement So in my textbook, they talk about have 2 coils; a primary coil that is connected in series with a battery and a switch, and a secondary coil in which is connected to a galvanometer. Now it says that when the switch in the primary circuit is closed, the meter in the...

Hello to all. What form would the magnetic field (due to the square loop) take? My understanding is that the current is changing, so the magnetic field will be changing.

I'm having a hard time understanding basic electromagnetic induction through wire loops. I can usually find out the EMF, but then I have a hard time finding the current in the loops. General advice on the matter would be extremely helpful. Thanks.

A 9.7 Ω resistor, a 10.8 µF capacitor, and a 27.9 mH inductor are connected in series with a 120 V (rms) source with variable frequency. (a) At what frequency will the current be maximum? Hz (b) Find the maximum rms current. A (c) Suppose you now replace the 10.8 µF...

Electromagnetic Induction!? HELP ! Homework Statement 1. A single horizontal loop of wire is moving in a horizontal plane at a constant speed across a uniform vertical magnetic field that "fills" and surrounds the loop. The emf induced across its terminals will be ...?? the answer was "none...

pleasezzzzzz anyone can clear me on this point: [SIZE="4"]why -ve sighn comes in faraday law of electro magnetic induction?what is it sighnificance?if in answer value of induce EMF become -ve than waht will be its direction.

Homework Statement A 10 cm by 10 cm square coil with 3 turns moves into a magnetic field 30 cm wide and of strength 10.0 T to the right of the diagram at a speed of 0.10 m/s as shown. http://two.xthost.info/joeykeys/1.png Sketch a graph of the induced voltage versus time, starting time...

Assume I can maintain the oscillation of a pendulum. Can I generate a practical amount of electric current by letting the pendulum oscillate in a magnetic field? (practical amount in this case means enough electricity to do useful work). 1)Do I need a series of pendula in their respective...

So, I have a few questions regarding some of the laws of electromagnetism. While I was in school, one of my classes was Electrodynamics (as an ECE undergrad). We discussed how a current through a conductor creates both magnetic and electric fields (Maxwell's equations, among others, were...

Hi, I am trying to learn more about electromagnetic induction because I want to build a generator for a wind turbine. I am a bit confused about something, hopefully someone out there can help me! I recently opened a bike dynamo. It contains a permanent magnet that can rotate, and the...

Insane Electromagnetic Induction Question. Challenge your brains! :D F=BIL, F=mg There is a B field acting on the rod so we resolve that. I tried to resolve the other force vectors according to: 1. Force acting on rod by gravity 2. Force acting on rod by electromagnetic (F=...

Whats the easiest way to test the max output of electricity induced in an air coil. I will wire it 3 phase delta. (or double delta) Will I need a resistive load attached for current flow? What should I use? How do I test? Use a multi tester? Is there math I can use to estimate the amount. I...

Homework Statement Whether a length of metallic wire, if placed in the geographic (a) east-west, and (b) north-south directions, and dropped freely from a height, would have an induced emf or not. Homework Equations E= - d(phi)/dt, where phi = flux intercepted by wire The Attempt at...

http://img30.imageshack.us/img30/7309/coil.png The figure shows a coil of wire in xy-plane with a magnetic field along y-axis. Around which of the three axis should the coil be rotated in order to generate emf and current in the coil? I think the answer is X and Z AXES because in these...

Electromagnetic Induction Problem : Help needed The flux density B in a region between the pole faces of a horse shoe magnet is 0.5T directed vertically downward. Find the emf induced in a straight wire 5cm long, perpendicular to B when it is moved in a direction at an angle of 60 degrees with...

Are electromagnetic waves always caused by a moving charge? A magnetic field can induce current in a conductor if the magnetic flux going through this conductor changes, is this reversible? So does an electric field cause a magnetic field because the electric flux ('through' what?) changes? Is...

Homework Statement The figure shows a 10-cm-diameter loop in three different magnetic fields. The loop's resistance is 0.10 ohm. http://i63.photobucket.com/albums/h148/jlmessick88/jfk_Figure_P25_12.jpg For case (a), what is the induced emf? ε = mV For case (a), what is the induced...

Homework Statement Hi! I have a problem with this exercise: A squared loop of length L and mass M can rotate around one of its vertices and it's on a vertical plane. In the region below the suspension point there is a uniform magnetic field B perpendicular to the plane of the loop. If the loop...

Why is there an iron core in a transformer? Is it necessary? In a transformer, how does the changing magnetic field on the primary induce a current on the secondary? Can we think of the changing magnetic field causing a changing force on the secondary and causing it to move back and forth...

Apologies for numerous posts today, I'm trying to catch up from work I missed last term, and my uni is on holiday at the moment so can't get help from lecturers. I've been set the following which I think I've got correct, but not 100%. Am I right in calculating the area in m2? Homework...

Homework Statement http://img407.imageshack.us/img407/5656/dsc02768iz3.jpg Examine the circuit shown in figure 12. When the switch is closed, assume the magnetic field produced by the solenoid is very strong. a) Explain what will happen to the copper ring (which is free to move) when...

Hi all, Could anyone pls explain me in detail (preferably with an example) what "change in magnetic flux" is...Thank you

A 20cm x 20cm square loop of wire lies in the xy-plane with its bottom edge on the x-axis. The resistance of the loop is 0.50\Omega. A uniform magnetic field parallell to the z-axis is given by B=0.80y^{2}t, where B is in tesla, y in meters, and t in seconds. What is the size of the induced...

Homework Statement The coil of an ac generator has an area per turn of 1.2x10-2m2 and consists of 500 turns. The coil is situated in a 0.13-T magnetic field and is rotating at an angular speed of 34 rads/s. What is the emf induced in the coil at the instant when the normal to the loop makes an...