What is Electromagnetic induction: Definition and 252 Discussions
Electromagnetic or magnetic induction is the production of an electromotive force across an electrical conductor in a changing magnetic field.
Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction. Lenz's law describes the direction of the induced field. Faraday's law was later generalized to become the Maxwell–Faraday equation, one of the four Maxwell equations in his theory of electromagnetism.
Electromagnetic induction has found many applications, including electrical components such as inductors and transformers, and devices such as electric motors and generators.
I have a conceptual issue with the following:
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.
My understanding is as follows:
The magnetic field of the Earth...
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...
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...
hi..i know the faraday's electromagnetic induction e=-dФ/dt...supposing there is an coil of wire and i am accelerating magnet through the coil of wire and this will produce emf because accelerating magnet results in change in magnetic field...my question is how to relate this acceleration a and...
There is a soft iron bar, with two coils wound at the two end. A current source is connected to the primary coil. A resistor is connected to the secondary coil.
So, the question is:
"Whether increasing the area of the secondary coil but keeping the area of the primary coil unchanged can...
Ok, I have two questions:
First of all, are there any instances in which a magnet (not an electromagnet) will remain magnetized forever? I know that some magnets do lost their magnetivity
Secondly, if the above is true then consider the following theoretical scenario:
Imagine a large Iron...
Homework Statement
4) The wing of an aircraft is 60m long and the aircraft is traveling at 250ms-1. The vertical component of the Earth’s magnetic field, which the wing is cutting, has the value of 4.3 X 10-5 T.
Calculate:
a. The Flux cut per second by the wing
b. The induced emf set up...
Hello!I would like to ask about Electromagnetic induction in transformer.As we learn that an alternating voltage is connected to the primary coil,the alternating current in the primary coil produces a magnetic flux linkage with the secondary coil which constantly changes.\phi=magnetic flux...
Hi,
I am learning Electromagnetic Induction in school and I have this question. For a straight conductor with length l and velocity v, that cuts through a uniform field, it can be seen that an emf is induced and this emf can be calculated using the equation E = Blv.
However, I would like...
[SOLVED] Electromagnetic induction
Homework Statement
You are given the following apparatus: copper ring, battery, variable resistor, lengths of insulated copper wire with connecting terminals at each end.
Describe, how you would use all of this apparatus to induce a current in the copper...
hi!
Actually am learning Lenz's law but am just getting confused.i know that the change of a magnetic field around a solenoid creates electricity. meaning that when we move the north pole of the magnet towards the end of the solenoid, the galvnometer deflects in one direction and when we move...
1)When the current through the coil of a motor flows it cases the coil to spin.
2)The spinning motion causes the wires in the coil to cut through the magnetic field.
3)The current induced (back EMF) in the wires by this spinning motion opposes the change that causes it. (Lenz's Law)...
The problem states:
A loop of area 4cm^2 has its plane parallel to the field lines of the magnetic field, B = 0.6t, as shown in the figure. The loop is pulled in the opposite direction of the field with a constant velocity of v = 6m/s.
I am confused as to solve this because I can't...
Question:
An automobile has a vertical radio antenna 1.2m long. The automobile travels at 65.0 km/h on a horizontal road where the Earth's magnetic field is 50.0 mT directed toward the north and downward at an angle of 65.0 degrees below horizontal.
calculate the magnitude of the induced...
E= -N \frac{d\phi_{B}}{dt}
Does this formula apply to any type of wire? If so, how?
It simply doesn't make sense to me that a magnetic field acting on a coil of copper would induce the same emf as if it was a coil, for instance, of aluminium.
This is the material i read from textbook, and it doesn't make any sense to me! can somebody please help me out if they can understand the concept:
To understand electromagnetic induction, we need to reconsider the concepts of electric
and magnetic fields.
A dc current I flowing through...
Homework Statement
A simple transformer is constructed by wrapping wire around opposite ends of an iron rod to form solenoids A and B. Solenoid A is connected to a 12-V battery and a variable resistor, while solenoid B is conncted to an ammeter.
http://f.exoload.com/507/homework.jpg
A. If...
How do I calculate the force (in Newtons) acting on a conductor moving through a magnetic field? This is in relation to an electromagnetic brake by the way; I need to work out the deceleration of train as it moves through the braking zone.
Thanks.
Homework Statement
I just got to two problems on my high school homework that i have no idea what to do because the teacher did not tell us how.
A generator can provide a maximum output emf of 170V. Calculate the rms potential difference.
Homework Equations
Do not know any relevant...
Aim: to test the Faraday relationship: induced e.m.f. equals the rate of change of magnetic flux linkage
flux linkage = NBA
N=number of turns in coil
B=magnetic flux density
A=area of the coil
To investigate the relationship above first i must have two quantities constant while the...
For Lenz’s Law, most examples involve the north pole of a bar magnet passing through first in a wire coil, or solenoid.
If the bar magnet’s north pole moves toward the loop or solenoid, the magnet’s magnetic field lines move from the south pole to north pole? The current in solenoid is then...
A piece of copper wire is formed into a single circular loop of radius 13 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.50 T in a time of 0.45 s. The wire has a resistance per unit length of 3.3 10-2 /m. What is the average electrical energy...
the question is that:
A rectangular loop with width L and a slide wire with mass m are as shown in Fig. A uniform magnetic field \vec B is directed perpendicular to the plane of the loop into the plane of the figure. The slide wire is given an initial speed of v_0 and then released. There is...
A piece of copper wire is formed into a single circular loop of radius 14 cm. A magnetic field is oriented parallel to the normal to the loop, and it increases from 0 to 0.75 T in a time of 0.45 s. The wire has a resistance per unit length of 3.3 x 10-2 ohm/m. What is the average electrical...
Please help! :confused:
I'm stuck on this homework question and it's due tomorrow.
Any help would be greatly appreciated...
Question:
A magnetic field of strength 2.3 T is directed into the plane of a square loop of wire with each side of length 0.4 m. The loop of wire is then crushed...
Well it looks like I need to find out as much as I can about Magnetic Induction. Does anyone have a link/ reference to a beginners understanding, study material so that I can start my Bob Sled project? In the mean time I'll search the physics textbooks on this site.
Thanks for all your help...
I am a third year aerospace engineering student with very little knowledge of eletricity generation. I currently cannot determine the simple derivation of Faraday's first (i think?) experiment of electromagnetic induciton (bar magnet passing through a loop).
Now i understand that the voltage...
A magnetic field is perpendicular to a 0.060 m 0.060 m rectangular coil of wire that has 100 turns. In a time of 0.070 s, an average emf of magnitude 1.5 V is induced in the coil. What is the magnitude of the change in the magnetic field?
My professor has not covered this in lecture yet, but...
I need to be enlightened on this. If a magnet with north pole facing towards a coil of wire is pushed in does it induce a current clockwise, or counterclockwise? If you push the coil in towards the magnet will it induce current in the opposite direction? How can I use the right hand rule with...
Hey I was wondering if anyone out there can help me. After doing some research I was not able to find out on my own. Well, the question I have is: does creating an electromagnetic field for the purpose of powering something (electromagnetic induction) create any harmful effects to anyone close...
A helicopter has 4 rotor blades attached to the central axis of rotation. (Like a + sign with the axis of rotation at the center.)
Each rotor blade is 5.2m long and spins at 6 revolutions per second perpendicular to the Earth's magnetic field of 0.047T. What is the emf induced between the...
Question:
0.2m x 0.2m metal loop is oriented vertically.
mass = 10g
resistance = 0.010Ω
magnetic field = 1.0 T
The magnetic field is horizontal (into the page), perpendicular to the loop, and fills the top half of the loop. There is no magnetic field in the bottom half of the loop.
The...
Having a little trouble understanding electromagnetic induction...
Do you produce more voltage when magnets are 'in series' or 'parallel?' I realize those might not be orthodox terms, so I'll try describe what I mean in words:
Say I have a few small permanent magnets to generate a current...
Again, this is a problem I got in my AP Physics Class can anyone help? I would really appreciate any help. My teacher didn't explain this concept too well.
A metal bar with length L, mass m, and resistance R is placed on frictionless, metal rails that are inclined at an angle \theta...
For my independent research project (grade 12) I've chosen to build a generator powered by a mounted bicycle based on electromagnetic induction.(we could choose anything we liked that had anything to do with what we learned during the term) The term has finished and we have two weeks off, I want...
I'm having some trouble with these two problems.
1.
A 1.2-m-long aluminum rod is rotating about an axis that is perpendicular to one end. A 0.16-T magnetic field is directed parallel to the axis. The rod rotates through one-fourth of a circle in 0.65 s. What is the magnitude of the average...
The magnetic field between the poles of an electromagnet is 2.6 T. A coil of wire is placed in this region so that the field is parallel to the axis of the coil. The coil has electrical resistance 25 , radius 1.9 cm, and length 15.0 cm. When the current supply to the electromagnet is shut off...
The generator of a car idling at 950 rpm produces 12.4 V. What will the output be at a rotation speed of 2500 rpm assuming nothing else changes?
I'm guessing that is easier and I'm looking to make it harder. I can't find anything in my textbook involving rpm. I'm thinkin to use this...
A constant magnetic field passes through a single rectangular loop whose dimensions are 0.348 m x 0.593 m. The magnetic field has a magnitude of 2.26 T and is inclined at an angle of 66.0° with respect to the normal to the plane of the loop. (a) If the magnetic field decreases to zero in a time...
Two 0.68 m long conducting rods are rotating at the same speed in opposite directions, and both are perpendicular to a 4.7 T magnetic field. As the drawing shows, the ends of these rods come to within 1.0mm of each other as they rotate. More-over, the fixed ends about which the rods are rotating...
Lets say there's a bar magnet going at a speed V (North pole first) through the central axis of symmetry of the circular coil.
Sketch the graph of the graph of the magnetic flux through the circular loop as a function of time. Also sketch the graph of the corresponding emf as a function of...
a) State Faraday’s law of electromagnetic induction.
[ mark
b) A coil of 1000 turns, resistance 23.0 ohms and cross-sectional area of 4.0 cm squared is positioned perpendicular to a magnetic field which is switched off in 0.005 s.
I) What is the average induced e.m.f. if the magnetic flux...