Lenz’s law and conservation of energy

The direction of the current induced during a conductor by a changing force field (as per Faraday’s law of electromagnetic induction) is such that the flux created by the induced current opposes the initial changing flux that produced it, in line with Lenz’s law of electromagnetic induction. Fleming’s manus rule determines the direction of this current flow.

• This can be difficult to understand initially, so let’s have a glance at an example scenario.
• This magnetic flux will always be the opposite to the force field that formed it in the first place.

The law of conservation of energy is the foundation of Lenz’s law. The induced current, in keeping with Lenz’s law, always tends to counter the cause that produces it. So, so as to figure against an opposing force, we must exert additional effort. As a result of the extra work, the magnetic flux changes on an everyday basis, causing more current to be produced. As a result, the additional effort is solely converted into the current, in accordance with the law of conservation of energy.

Law of conservation of energy :

It has the ability to transform from one form to another. This signifies that the overall amount of energy is constant. When a stone starts rolling downhill, its potential energy transforms to kinetic energy, as we taught in the mechanical energy section.

The law of conservation of energy asserts that the entire energy of an isolated system remains constant; it’s stated to be conserved across time in physics and chemistry.  Energy can not be generated or destroyed, consistent with this law, which was initially proposed and tested by Émilie du Châtelet. It can only be converted or moved from one form to another. When a stick of dynamite explodes, energy is transferred to mechanical energy. When all styles of energy released within the explosion are added together, like the kinetic and P.E. of the fragments, also as heat and sound, the precise energy within the dynamite combustion could also be calculated.

Pushing the magnet into the coil and pulling it out against the magnetic influence of the induced current requires only a bit of effort. Because the induced current encounters resistance within the coil’s material, the tiny quantity of energy represented by this work expresses itself as a modest heating effect. The overall idea of energy conservation is upheld by Lenz’s law. If the present was induced within the other direction, additionally to the heating effect, it might draw the magnet into the coil on its own, violating energy conservation.

Lenz’s law

He characterised the magnetic flux’s direction in relation to the direction of electric current. He deduced that an induced current in a circuit has a direction that is opposite to the change that creates it.

Key facts about Lenz’s Law

• Magnetic fields produced by strong magnets can induce counter-rotating current in copper or aluminium pipes.
• This law shows that the induced emf and therefore the change in flux have opposite signs, proving Faraday’s Law of Induction’s sign choice.
• Electric generators are likewise subject to the current rule.
• The basic concepts of stored magnetic energy in an inductor may be understood using Lenz’s Law.

Applications of Lenz’s Law in daily life

• Train braking systems, metal detectors, and eddy current dynamometers
• Generators for alternating current,
• Readers of cards,
• Microphones.

 The law that gives the polarity of the induced emf :

The polarity of the induced emf is determined by Lenz’s Law when the emf is induced by a change in the magnetic flux according to Faraday’s Law.

The Law of Lenz:

In 1834, Heinrich Lenz proposed Lenz law. Faraday’s law of electromagnetic induction provides us with a notion of the quantity of the electromotive force which is generated across the circuit, and Lenz’s law lets us figure out which way the electric current is flowing through the whole circuit. The induced current direction in the coil is in a way that it opposes changes that cause the induced emf, according to Lenz’s law. Or, to put it another way, the current direction will be the polar opposite of the flux that produces it.

(d𝜙B/dt ) = -E 

-The induced e.m.f. opposes the change in magnetic flux, as indicated by the -ve sign.

Experiment :

1st Experiment 

This experiment was started by Emil Lenz when the current passing through the circuit’s coil, magnetic field lines are generated. 

2nd Experiment

In the second experiment, Lenz claimed that an induced current would be generated if the current-carrying coil was wound over the iron rod with his left end acting as an N-pole and turned toward the ‘S’ coil.

3rd Experiment

Lenz noted within the third experiment that when the coil is moved within the magnetic flux direction, the coil that’s related to it reduces. As a result of Lenz’s law, once the induced current is delivered in a very comparable direction, the coil’s motion is confined.

The field of force exerts a force over the coil to get an induced current, while this supply exerts a force on the force field to limit it.

What is Energy?

We are hard at work. We require energy to do our tasks. As a result, energy conservation is defined as the ability to perform any task.

Work is the change that occurs in an object as a result of a force being applied to it. Work is said to be done when a force is applied to an object that causes it to travel a distance or change its shape.

Work = force × distance

This concept of work applies to both living and non-living things. Energy and work share the same unit, the Joule because energy is the capacity to accomplish work.

Conclusion

• Lenz Law gives the direction of induced emf 
• The general idea of energy conservation is upheld by Lenz’s law. 
• If the current was induced in the other direction, in addition to the heating effect, it would draw the bar magnet into the coil on its own, violating energy conservation.
• Whenever the magnetic flux increases or decreases the induced emf is set up in the circuit