A coil is moved through a magnetic field as shown below. The field is uniform inside the rectang

A coil is moved through a magnetic field as shown below. The...

Key Concepts

Fleming’s Right-Hand Rule

Fleming’s right-hand rule is a mnemonic used to determine the direction of induced current in a generator. By aligning the thumb, forefinger, and middle finger perpendicularly, one can correlate the motion of a conductor through a magnetic field with the resulting direction of the induced current, reinforcing the principles outlined in Lenz’s law.

Electromagnetic Induction

Electromagnetic induction is the process by which a changing magnetic environment produces an electric current in a conductor. This fundamental phenomenon underlies many electrical generators and transformers, where motion or time-varying fields change the magnetic flux through a circuit, thereby inducing an electromotive force (EMF) and current.

Magnetic Flux

Magnetic flux quantifies the amount of magnetic field passing through a given area. It is a critical concept in induction because changes in the flux, due to motion or variations in the field strength, directly lead to the generation of an induced EMF in the conductor according to Faraday’s law.

Faraday’s Law of Induction

Faraday’s law states that the magnitude of the induced EMF in a circuit is proportional to the rate of change of the magnetic flux through the circuit. This law provides the quantitative relation needed to analyze how variations in a magnetic field or the area exposed to it lead to induced currents.

Lenz’s Law

Lenz’s law gives the direction of the induced current resulting from a change in magnetic flux. It asserts that the induced current will flow in such a way that its own magnetic field opposes the change in the original magnetic flux, thus conserving energy and obeying the principle of action and reaction.

Motional EMF

Motional EMF is the voltage generated across a conductor moving through a stationary magnetic field. As the conductor cuts through magnetic field lines, the charges within experience a Lorentz force that separates them, thereby creating a potential difference and driving a current if the circuit is closed.

Lorentz Force

The Lorentz force is the force experienced by a charged particle moving in a magnetic field, given by the vector cross product of the particle’s velocity and the magnetic field. In the context of current-carrying conductors, this force results from the collective action on moving charges and determines the direction of the magnetic force on the coil as it interacts with the magnetic field.

Transcript

00:01 Hi, in the given problem there is a magnetic field which is coming out of the plane of paper perpendicularly and a circular coil is passing through this magnetic field as shown here in the figure in the first case the coil is entirely out of the magnetic field in second case it starts entering into the magnetic field in third case it is moving entirely within the magnetic field in fourth case the coil starts coming out of the magnetic field and in last case the coil is again entirely out of the magnetic field the motion of the coil is always towards right we have to find the direction of the current induced in the coil and the direction of force acting on the coil in all the cases in the first case as the coil is entirely out of the field so no magnetic flux linked through it so no emf or current induced in it and no force acting on it now in the second part of the problem the coil starts entering into the magnetic field and the magnetic field is in outward direction so we can say the reason behind the emf induced because we can say the emf will be induced in this case as the magnetic flux linked through the coil is changing so as per faraday's laws of electromagnetic induction now the emf and hence the current will be induced in the coil whose reason is outward increasing magnetic flux so as per lens's law a magnetic flux will be induced in it whose direction will be such that it may oppose the reason behind it so the opposition will be inward increasing magnetic flux and we know the the magnetic field enters into the south pole.

03:07 So the face of the coil should start beginning like south pole and the direction of current induced in it in the coil should be clockwise.

03:20 Now as the coil is moving towards right, so a force should act on the coil in leftward direction again as per lens is law.

03:30 So the force acting on the coil should be leftward.

03:47 So as to oppose the rightward motion of the coil, again as per lenses law.

04:08 In third position of the coil, the coil is entirely within the magnetic field, entirely within the magnetic field, entirely within the magnetic field...

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