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### electromagnetic induction - Why doesn't current cancel in a generator?

I am a little confused about the application of Faraday's law in a generator. If we imagine a magnet attached to a wheel (which spins when water falls on it) next to a coil, as the magnet spins around, current will be generated due to electromagnetic induction. However, when we measure the current, the needle on the galvanometer swings back and forth. Why doesn't the current cancel out when it goes from positive to negative on the galvanometer?...Read more

### electromagnetic induction - Faradays law and rate of change of flux

consider a table with the a uniform magnetic field of flux density B coming directly out of it, the field lines are perpendicular to the the surface of the table, pointing up and out. let a loop of wire enclosing area A lie on the surface of the table, then flux through the loop is AB. let me move the loop ALONG the table surface to another part of table in time T. since the field is uniform the flux through the loop here is also AB. By Faradays law the induced emf is rate of change of flux through loop which is (AB-AB)/T = 0. but how is this p...Read more

### electromagnetic induction - Does Lenz's law imply the total flux (sum of the magnetic flux due to the moving magnet & that due to induced current) through the loop is constant?

The induced emf is given by the formula $$\varepsilon = -\frac{d\Phi}{dt}\;.$$Lenz's Law tells that The direction of the induced current be such that it opposes the change that has induced it.So, that means the current would be induced such that it counteracts the change in magnetic flux through the loop caused due to the approaching of the magnet.If the flux is increasing when the north pole of the magnet approaches the loop, there would be counter-clockwise current so that it counteracts the change of magnetic flux of the moving magnet towa...Read more

### Why is magnetic flux used to measure induced emf? And some other questions on electromagnetic induction

I fail to see why magnetic flux in particular is related to how strong an induced emf is, and not some other value.Magnetic flux , from what I understand, is the number of magnetic field lines passing through a given area in the normal direction, or the strength of magnetic field in the normal direction through a given area.Why is it that when calculating the induced emf in a loop of wire, we use flux? The area that's used for the flux is the area of the plane of the loop, but isn't that space in many cases just air? It's not the conducting mat...Read more

### electromagnetic induction - Will Emf induce in current carrying conductor in solenoid?

If a current carrying conductor is placed inside a solenoid where current passes through both solenoid & conductor, Will an extra emf(potential difference)/current induce in the conductor? [current in conductor is less than that of solenoid]?Let emf already existing in conductor be E1.If emf is induced:Assume emf induced by solenoid to be E2.Will the emf induced be E1+E2 or E2 or any other value?Please answer soon......Read more

### Total changing flux in Faraday Lenz law of induction

To clarify my question, I made the illustration below, assuming I understood the Faraday-Lenz law:Above a copper loop theoretically stays in parallel between the plates A and B.The magnetic field B hence the flux between the plates A and B is continuously increased. The copper loop circulates a current such that to oppose the increasing flux.Above I showed the directions of increasing flux and self generated opposing flux.My question is, will the total changing flux always be zero no matter the conductor is perfect or not? If the applied flux w...Read more

### electromagnetic induction - How does change in magnetic flux density only induce EMF?

Faraday's law states that Induced EMF is equal to rate of change of magnet flux linkage. Magnetic flux linkage is equal to the product of number of turns, area, and magnetic flux density. So EMF can be induced by changing the area, or magnetic flux density. I can understand that changing the area means moving electrons, which generate magnetic fields that interact with other magnetic fields to produce EMF. What I don't understand is how does changing magnetic flux density also produce EMF?? Take a transformer as an example: Alternating Current ...Read more

### electromagnetic induction - Understanding the induced EMF by a magnet through a solenoid

I just started self-studying physics again after some 20 years and I'm confused by this. So assume I have a wire loop and I move a magnet quickly through it. Then there will be an induced current $I$ in the loop. Now by Ohm's law, we get $V=IR$, so there's a potential difference somewhere. My question is where? Between what points would I find the potential difference? How should I conceptually think about this?I can wrap my head around this in the case of a battery, where there are typically ions moving inside the battery against an electric f...Read more

Is it just an experimental fact that changing magnetic flux through a loop induces current in the loop(Faraday's law) or could we explain it with some reasoning?...Read more

### electromagnetic induction - Induced current in circuit with falling side

There is a physics problem from the 2016 version of national test about induction that I'm not certain about. In it, there are two long standing vertical metal rods connected by a horizontal resistor. A horizontal rod is allowed slide down the two vertical rods, and the whole setup is bathed in a magnetic field B, perpendicular to the plane of the loop. As the rod falls, the area of circuit and thus the flux increases. The problem involves solving for the induced current, and also the equation of motion with the rod reaching a terminal veloc...Read more

### electromagnetic induction - Magnetic field in two different medium

From Faraday's law of induction we know if we have a coil with ac current it will create ac current to other coil placed within magnetic field. My question is if one coil is in water and another coil is in air what will be the pattern of magnetic field?...Read more

### electromagnetic induction - Will the constant of mutual inductance change?

Will the value of mutual inductance be different when the initial primary coil is connected to a voltmeter and the initial secondary coil is connected to the power supply?(which means the initial primary coil is now the secondary coil) From what I thought, that constant should change as the number of primary coil and the length of the primary coil is different from initial value of the primary coil....Read more

### electromagnetic induction - The fate of a bar magnet released in an infinitely long copper tube

A bar magnet is released under gravity inside a long copper tube along the axis of the tube. The answer is given (edit :) it moves with constant velocity. But I don't understand how.My research : The bar magnet is falling with an acceleration of $g$. So its speed increases. Thus the flux change also increases with time. And thus ultimately, the induced emf also changes as induced emf is directly proportional to the change of magnetic flux through the loop (the copper tube consists of infinite copper loops).Now according to Lenz's Law, the induc...Read more

### How magnetic induction works

What exactly is happening to the electrons inside the wire while it is moving quickly downwards within the magnetic field?Why do electrons move in one direction if the wire is being pushed down?I don't care what direction electrons move. I want to know why they move in one direction?...Read more

### electromagnetic induction - Basic Transformer Question

My understanding of how a transformer works is that there is a primary and a secondary coil wrapped around a common iron coil. An alternating current in the primary coil results in a changing magnetic field which in turn results an induced current in the secondary coil.The resulting voltage across secondary coil is proportional the the number of turns in the secondary coil. My understanding of this is that each loop produces a small emf and these loops are all in series so adding more loops is like adding more cells in series in a battery.My ...Read more