DHS 17 Electromagnetic Induction (Notes & Tutorial)

Dunman High School (Senior High Physics) 1 Topic 17 – Electromagnetic Induction Guiding Questions  If an electric current produces a magnetic field, can a magnetic field produce an electric current? What is required for this?  Can we achieve perpetual motion by invoking the magic of electromagnetism? Content  Magnetic flux  Laws of electromagnetic induction Learning Outcomes Candidates should be able to a. define magnetic flux as the product of an area and the component of the magnetic flux density perpendicular to that area b. recall and solve problems using  = BA c. define magnetic flux linkage d. infer from appropriate experiments on electromagnetic induction: i. that a changing magnetic flux can induce an e.m.f. ii. that the direction of the induced e.m.f. opposes the change producing it iii. the factors affecting the magnitude of the induced e.m.f. e. recall and solve problems using Faraday’s law of electromagnetic induction and Lenz’s law f. explain simple applications of electromagnetic induction Introduction In the previous topic on Electromagnetism, we learned that when a current flows through a conductor in a magnetic field, it experiences a force. This phenomenon, governed by Fleming’s Left Hand Rule, can cause the conductor to move. But what if, instead of supplying a current, we apply a force to move the conductor through the magnetic field? Could this generate a current? The answer lies in the principle of Electromagnetic Induction, which forms the foundation of how electricity is generated in power plants and countless other systems. To understand this process, we must first explore the concept of magnetic flux and the fu ndamental laws of electromagnetic induction.

Dunman High School (Senior High Physics) 2 17.1 Magnetic Flux Magnetic field lines visually represent the strength and direction of a magnetic field. However, in certain situations, it is important to quantify how much of the magnetic field penetrates a given surface. This is where the concept of magnetic flux comes in. Magnetic flux measures the total number of magnetic field lines passing through a specific area A and helps us analyse the interaction between magnetic fields and surfaces. Magnetic Flux is defined as the product of an area and the component of the magnetic flux density perpendicular to that area. For a uniform magnetic flux density B at an angle θ to the normal of an area A, the magnetic flux Φ is given by cosB A BA    The SI unit of magnetic flux is the weber (symbol: Wb). 17.1.1 Magnetic Flux Linkage If the area A is bounded by a coil and the coil has N turns, then the total magnetic flux passing through the coil, also known as magnetic flux linkage through the coil, is cosN NBA  Magnetic Flux Linkage is the product of the magnetic flux passing through the coil and the number of turns on the coil.