michael faraday | law of electromagnetic induction | faraday's law of induction

Electromagnetic induction
21 Jun 202109:29
EducationalLearning
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TLDRThis video discusses Faraday's Law of Electromagnetic Induction, exploring the phenomenon discovered by Michael Faraday in 1831 and Joseph Henry in 1832. It explains the experiment involving a coil and a bar magnet, demonstrating how electric current is induced in the coil due to changes in magnetic flux. The video clarifies that the induction of current occurs not because of the motion of the magnet itself but due to the change in magnetic flux. Additionally, it explains Faraday's first and second laws of electromagnetic induction, emphasizing the relationship between changing magnetic flux and induced electromotive force (EMF).

Takeaways
  • 🔬 The Faraday's Law of Electromagnetic Induction was first discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832.
  • 📚 Faraday was the first to publish the results of his experiments, demonstrating that a changing magnetic field induces an electric current.
  • 🧲 The experiment involves a simple coil connected in series with a galvanometer and a permanent bar magnet, representing the north and south poles respectively.
  • 📉 When the bar magnet is moved towards the coil, the deflection of the needle in the galvanometer indicates the presence of an electric current, which is a result of electromagnetic induction.
  • 🛑 Stopping the movement of the bar magnet stops the indication of electric current in the galvanometer, showing that the induction is due to the motion of the magnet.
  • 🔄 The direction of the induced current changes when the magnet is moved away from or towards the coil, demonstrating that the current is induced by the change in magnetic flux, not the motion itself.
  • 🔋 The experiment also explains how a battery can be charged by connecting it in series with the coil, as the induced current can charge the battery.
  • ⚡ The phenomenon of electromagnetic induction was first observed by Faraday and is known as Faraday's first law of electromagnetic induction, which deals with the induced electromotive force and current.
  • 🌀 Faraday's second law of electromagnetic induction explains that the induced electromotive force is equal to the rate of change of magnetic flux over time.
  • 🔧 The experiment can be visualized by moving the bar magnet more rapidly, which induces a higher electromotive force and a larger induced current.
  • 🔔 The video emphasizes the importance of understanding the relationship between the change in magnetic flux and the induction of electric current, and how this principle is applied in various technologies.
Q & A

  • What is the phenomenon of electromagnetic induction?

    -Electromagnetic induction is the process by which an electromotive force (EMF) or voltage is generated in a conductor due to a changing magnetic field around it.

  • Who first discovered the phenomenon of electromagnetic induction?

    -The phenomenon of electromagnetic induction was first discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832.

  • What was the significance of Faraday's experiments on electromagnetic induction?

    -Faraday's experiments were significant as they were the first to publish the results, demonstrating that a changing magnetic field could induce an electric current.

  • What is a galvanometer and how is it used in the context of electromagnetic induction?

    -A galvanometer is a sensitive instrument used to detect and measure small electric currents. In the context of electromagnetic induction, it is used to observe the deflection of a needle, indicating the presence of an induced electric current when a magnetic field changes around a coil.

  • How does the direction of the magnetic field lines affect the deflection of the needle in a galvanometer?

    -The direction of the magnetic field lines determines the direction of the deflection of the needle in a galvanometer. If the magnetic field lines are entering from one side and exiting from the other, the needle will deflect in one direction, and vice versa.

  • What happens when a bar magnet is moved towards and away from a coil in the experiment?

    -When a bar magnet is moved towards a coil, the magnetic field lines change, inducing an electric current that causes the needle in the galvanometer to deflect. When the magnet is moved away, the needle deflects in the opposite direction due to the change in the magnetic field.

  • Why does the galvanometer not show any indication of electric current when the bar magnet is stationary?

    -The galvanometer does not show any indication of electric current when the bar magnet is stationary because there is no change in the magnetic field lines, and thus no induction of electric current.

  • What is the relationship between the motion of the magnet and the induction of electric current?

    -The induction of electric current is related to the change in the magnetic field lines, which is caused by the motion of the magnet. It is not the motion of the magnet itself that induces the current, but the change in the magnetic field it produces.

  • How does the rate of change of the magnetic field affect the induced electric current?

    -The rate of change of the magnetic field is directly proportional to the magnitude of the induced electric current. A faster change in the magnetic field will induce a higher electromotive force and, consequently, a stronger electric current.

  • What is the significance of Faraday's second law of electromagnetic induction?

    -Faraday's second law of electromagnetic induction states that the induced electromotive force in a conductor is equal to the negative rate of change of magnetic flux through the conductor. This law helps to understand the relationship between the change in magnetic field and the induced current.

  • What happens when the circuit is closed during the experiment?

    -When the circuit is closed, the induced electric current can flow through the circuit, and the galvanometer connected in series will show a deflection indicating the presence of the current. This is due to the change in magnetic flux linking the coil.

  • Why is it important to understand the direction of the induced current in electromagnetic induction?

    -Understanding the direction of the induced current is important because it is determined by Lenz's law, which states that the induced current will flow in such a way as to oppose the change in magnetic flux that produced it. This is crucial for predicting the behavior of systems involving electromagnetic induction.

Outlines
00:00
🔬 Faraday's Law of Electromagnetic Induction

This paragraph discusses Faraday's Law of Electromagnetic Induction, discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832. It explains the phenomenon where a change in the magnetic field within a coil induces an electric current. The paragraph describes an experiment involving a galvanometer, a coil, and a bar magnet to demonstrate this effect. It clarifies that the deflection seen in the galvanometer's needle is due to the electric current induced by the change in the magnetic field lines, not the motion of the magnet itself. The importance of the closed circuit for the induction of electric current is also highlighted.

05:02
🌐 Understanding Electromagnetic Induction and Magnetic Flux

The second paragraph delves deeper into the concept of electromagnetic induction, focusing on the role of magnetic flux and how it induces electric current in a conductor. It explains that the magnetic field of a coil can change from zero to its highest value, inducing a current in the coil for an instant. The paragraph mentions Faraday's First Law of Electromagnetic Induction, which relates to the induced electromotive force (EMF) and current but does not explain what causes the magnetic law. It also touches upon Faraday's Second Law, which quantifies the relationship between the rate of change of magnetic flux and the induced EMF. The paragraph concludes by encouraging viewers to like, subscribe, and turn on notifications for more educational content.

Mindmap
Keywords
💡Electromagnetic Induction
Electromagnetic induction is the process by which an electromotive force (EMF) is generated in a conductor due to a changing magnetic field around it. In the video's context, it is the core phenomenon that Faraday's experiments were based on, which led to the discovery of how a changing magnetic field can induce an electric current. The script mentions 'Faraday's law of electromagnetic induction' and describes experiments showing the deflection of a needle in a galvanometer as evidence of electric current induction.
💡Faraday
Michael Faraday was a British scientist who made significant contributions to the field of electromagnetism and is best known for his discovery of electromagnetic induction. The script refers to him as the first to publish the results of his experiments on electromagnetic induction in 1831, which laid the groundwork for the understanding of how electric currents can be generated without direct contact.
💡Galvanometer
A galvanometer is an instrument used for detecting and measuring small electric currents. In the script, it is used to demonstrate the presence of electric current induced by moving a bar magnet towards and away from a coil. The deflection of the needle in the galvanometer indicates the induction of electric current due to the changing magnetic field.
💡Magnet
A magnet is an object or material that produces a magnetic field and attracts other magnetic materials. The script discusses the use of a bar magnet in Faraday's experiments, where the magnet's movement relative to a coil induces an electric current. The magnet's north and south poles are specifically mentioned as the source of the magnetic field lines that interact with the coil.
💡Magnetic Flux
Magnetic flux is a measure of the total magnetic field that passes through a given area. The script explains that the change in magnetic flux through the cross-section of a coil is what induces an electric current. The concept is central to understanding electromagnetic induction, as it is the variation in magnetic flux that causes the current to be generated.
💡Electric Current
Electric current is the flow of electric charge, typically through a conductor. The script describes how the movement of a magnet induces an electric current in a coil, which can be observed through the deflection of a needle in a galvanometer. The presence or absence of this current is a key indicator of electromagnetic induction.
💡Magnetic Field Lines
Magnetic field lines are a visual representation of the direction and strength of a magnetic field. In the script, they are mentioned as emerging from the north pole and entering the south pole of a bar magnet. These lines are crucial in illustrating how the magnetic field interacts with the coil in Faraday's experiments.
💡Induced EMF
Induced EMF, or electromotive force, is the voltage generated in a conductor due to a changing magnetic field. The script explains that when the magnetic field lines link with the coil, an induced EMF is created, which in turn induces an electric current if the circuit is closed. This is a fundamental aspect of electromagnetic induction.
💡Circuit
A circuit is a closed loop through which electric current can flow. The script mentions that for an induced current to be observed in the galvanometer, the coil must be part of a closed circuit. The opening and closing of the circuit are highlighted as they affect the presence of the induced current.
💡Faraday's Law of Electromagnetic Induction
Faraday's Law of Electromagnetic Induction states that the induced EMF in a closed circuit is proportional to the rate of change of magnetic flux through the circuit. The script refers to this law when explaining the experiments and the conditions under which an electric current is induced, emphasizing the importance of the change in magnetic flux rather than the motion of the magnet itself.
💡Magnetism
Magnetism is the property of objects that attracts materials such as iron, and it is a fundamental concept in the study of electromagnetism. The script discusses the magnetic properties of the bar magnet used in the experiments and how the magnet's interaction with the coil leads to the induction of electric current. The term is used to describe the force that causes the observed effects in Faraday's experiments.
Highlights

Introduction to Faraday's Law of Electromagnetic Induction.

Discovery of electromagnetic induction independently by Michael Faraday in 1831 and Joseph Henry in 1832.

Faraday's experiment demonstrating the induction of electric current when a bar magnet is moved toward a coil.

Explanation of how magnetic flux changes as a magnet moves closer to or away from a coil, inducing an electromotive force (EMF).

Clarification that the induction of electric current is due to the change in magnetic flux, not the motion of the magnet itself.

Experiment replacing the magnet with another coil to demonstrate that the induced EMF is due to the change in magnetic flux.

Observation that the electric current is induced in the adjacent coil when the circuit is closed or opened, even without a moving magnet.

Introduction to Faraday's First Law of Electromagnetic Induction: A change in magnetic flux linking to a conductor induces an electromotive force (EMF).

Explanation of how the magnitude of induced EMF and current depends on the rate of change of magnetic flux.

Demonstration of how moving a magnet more rapidly increases the induced EMF and current in the conductor.

Mathematical expression of Faraday's Law: EMF (e) is equal to the change of magnetic flux (dΦ) over time (dt).

Summarization of the discussion on how current is induced in a conductor and the factors that determine its magnitude.

Reminder to like the video, subscribe to the channel, and press the bell icon for notifications of new uploads.

Transcripts

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