General Physics 2 12 General Physics 2 – Grade 12 Quarter 4 – Module 1: Electromagnetic Induction First Edition, 2020 Republic Act 8293, Section 176 states that no copyright shall subsist in any work of the Government of the Philippines. However, prior approval of the government agency or office wherein the work is created shall be necessary for the exploitation of such work for a profit. Such agency or office may, among other things, impose as a condition the payment of royalties. Borrowed materials (i.e., songs, stories, poems, pictures, photos, brand names, trademarks, etc.) included in this module are owned by their respective copyright holders. Every effort has been exerted to locate and seek permission to use these materials from their respective copyright owners. The publisher and authors do not represent nor claim ownership over them. Published by the Department of Education - Schools Division of Pasig City Development Team of the Self-Learning Module Writer: Maria Allen B. Secretario Editor: Melvina S. Tarcena Reviewer: Melvina S. Tarcena / SLRC Illustrator: Layout Artist: Bren Kylle A. Aveno Management Team: Ma. Evalou Concepcion A. Agustin OIC-Schools Division Superintendent Carolina T. Revera, CESE Assistant Schools Division Superintendent Manuel A. Laguerta EdD Chief, Curriculum Implementation Division Education Program Supervisors Librada L. Agon EdD (EPP/TLE/TVL/TVE) Liza A. Alvarez (Science/STEM/SSP) Bernard R. Balitao (AP/HUMSS) Joselito E. Calios (English/SPFL/GAS) Norlyn D. Conde EdD (MAPEH/SPA/SPS/HOPE/A&D/Sports) Wilma Q. Del Rosario (LRMS/ADM) Ma. Teresita E. Herrera EdD (Filipino/GAS/Piling Larang) Perlita M. Ignacio PhD (EsP) Dulce O. Santos PhD (Kindergarten/MTB-MLE) Teresita P. Tagulao EdD (Mathematics/ABM) Printed in the Philippines by the Department of Education – Schools Division of Pasig City Physics 2General 12 Quarter 4 Self-Learning Module 1 Electromagnetic Induction Introductory Message For the Facilitator: Welcome to the General Physics 2 Grade 12 Self-Learning Module on Electromagnetic Induction! This Self-Learning Module was collaboratively designed, developed, and reviewed by educators from the Schools Division Office of Pasig City headed by its Officer-in-Charge Schools Division Superintendent, Ma. Evalou Concepcion A. Agustin, in partnership with the City Government of Pasig through its mayor, Honorable Victor Ma. Regis N. Sotto. The writers utilized the standards set by the K to 12 Curriculum using the Most Essential Learning Competencies (MELC) in developing this instructional resource. This learning material hopes to engage the learners in guided and independent learning activities at their own pace and time. Further, this also aims to help learners acquire the needed 21st-century skills especially the 5 Cs, namely: Communication, Collaboration, Creativity, Critical Thinking, and Character while taking into consideration their needs and circumstances. In addition to the material in the main text, you will also see this box in the body of the module: Notes to the Teacher This contains helpful tips or strategies that will help you in guiding the learners. As a facilitator, you are expected to orient the learners on how to use this module. You also need to keep track of the learners' progress while allowing them to manage their learning. Moreover, you are expected to encourage and assist the learners as they do the tasks included in the module. For the Learner: Welcome to the General Physics 2 Self-Learning Module on Electromagnetic Induction! This module was designed to provide you with fun and meaningful opportunities for guided and independent learning at your own pace and time. You will be enabled to process the contents of the learning material while being an active learner. This module has the following parts and corresponding icons: Expectations - This points to the set of knowledge and skills that you will learn after completing the module. Pretest - This measures your prior knowledge about the lesson at hand. Recap - This part of the module provides a review of concepts and skills that you already know about a previous lesson. Lesson - This section discusses the topic in the module. Activities - This is a set of activities that you need to perform. Wrap-Up - This section summarizes the concepts and application of the lesson. Valuing - This part integrates a desirable moral value in the lesson. Posttest - This measures how much you have learned from the entire module. EXPECTATIONS The module is about Faraday’s Law for Electromagnetic Induction. After going through this module, you are expected to: 1. identify the factors that affect the magnitude of the induced emf (electromotive force) and direction of the induced current (Faraday’s Law); 2. compare and contrast electrostatic electric nonelectrostatic/induced electric field; and field and 3. recognize some applications of electromagnetic induction. PRETEST Choose the letter of the BEST correct answer. Write the chosen letter in your notebook. 1. A voltage will be induced in a wire loop when the magnetic field within that loop A. changes B. aligns with the electric field C. is at the right angle to the electric field D. converts to magnetic energy 2. If you change the magnetic field in a closed loop of wire, you induce in the loop a A. current B. voltage C. electric field D. all of the above A. 3. Which of the following equations correctly describes Faraday’s law of induction? A. B. C. D. 4. The essential concept in an electric motor and a generator is B. Coulomb’s law C. Ohm’s law D. Faraday’s law E. Newton’s second law 5. Which of the following would not increase the emf produced by a generator? A. rotating the generator coil faster B. increasing the strength of the generator magnets C. increasing the number of turns of wire in the coil D. reducing the cross-sectional area of the coil RECAP Given the different illustration of a magnet, complete the table by giving some characteristics and properties of the magnetic field: (Photo Credits: Presenta0onExpress Conceptual Physics, Pearson) (Photo Credits: Google Image) (Photo Credits: Presenta0onExpress Conceptual Physics, Pearson) (Photo Credits: Google Image) LESSON Copyright © h,ps://google/images A B Are you familiar with picture A? How about picture B? How do these objects work? What can you say about the picture on the left? Can you light a bulb or detect current without any power source or battery? How? Copyright © : PresentationExpress Conceptual Physics ELECTROMAGNETIC INDUCTION: In 1831, two physicists, Michael Faraday in England and Joseph Henry in the United States, independently discovered that magnetism could produce an electric current in a wire. Their discovery was to change the world by making electricity so commonplace that it would power Copyright © industries by day and light up cities by night. They discovered the principle of electromagnetic induction at almost by the the same time but in countries separated h,ps://images.app.goo.gl/V9h4FvZvfmXu1u7C8h,ps://image s.app.goo.gl/V9h4FvZvfmXu1u7C8 ocean! To see how an emf can be induced by a changing magnetic field, copy this link on your browser and explore the simulation with the bar magnet and the coil of wire, using the ammeter or the bulb as an indicator or sensor https://phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation= generator In the simulation, try to move the bar magnet in and out of the coil and observe the bulb and the direction of the ammeter needle. Change the speed of the motion of the bar magnet and take note of your observations. Consider a loop of wire connected to a galvanometer. When a magnet is moved toward the loop, the galvanometer needle deflects in one direction, as shown in figure a. When the magnet is moved away from the loop, the needle deflects in the opposite direction, as shown c. When the magnet is held stationary relative to the loop in figure b, no deflection is observed. Finally, if the magnet is held stationary and the loop is moved either toward or away from it, the needle deflects. From these observations, we conclude that the loop “knows” that the magnet is moving relative to it because it experiences a change in a magnetic field. Thus, it seems that a relationship exists between current and changing magnetic fields. Copyright © : Physics, Serway 5th Edition, Faraday’s Law of Induction A current is set up even though no batteries are present in the circuit! We call such a current an induced current and say that it is produced by an induced emf. FARADAY’S EXPERIMENT: Ø A primary coil is connected to a switch and a battery. Ø The wire is wrapped around an iron ring. Ø A secondary coil is also wrapped around the iron ring. Ø There is no battery present in the secondary coil. Ø The secondary coil is not connected to the primary coil. Ø At an instant the switch is closed, the ammeter changes from zero in one direction and then returns to zero. Ø When the switch is opened, the ammeter changes in the opposite direction and then returns to zero. Ø The ammeter reads zero when there is a steady current or when there is no current in the primary circuit. An electric current can be induced in a loop of wire by changing the magnetic field. This would be the current in the secondary circuit. The induced current exists only while the magnetic field through the loop is changing. Therefore, an induced emf (electromotive force) is produced in the loop by the changing magnetic field. Faraday concluded that an electric current can be induced in a circuit (the secondary circuit in our setup) by a changing magnetic field. In effect, the secondary circuit behaves as though a source of emf were connected to it for a short time. It is customary to say that an induced emf is produced in the secondary circuit by the changing magnetic field. FARADAY’S LAW OF ELECTROMAGNETIC INDUCTION: The emf (electromotive force) induced in a circuit is directly proportional to the time rate of change of the magnetic flux through the circuit. Mathematically, If the circuit consists of N loops, Faraday’s law states that the induced voltage in a coil is proportional to the product of the number of loops, the cross-sectional area of each loop, and the rate at which the magnetic field changes within those loops. The magnetic flux is given by 𝝓𝒎 = 𝑨𝑩 𝒄𝒐𝒔 𝜽. Ways of Inducing an emf: 1. The magnitude of the magnetic field can change in time. 2. The area enclosed by the loop can change with time. 3. The angle between the magnetic field and the normal to the loop can change with time APPLICATION OF ELECTROMAGNETIC INDUCTION: Electromagnetic Induction is the production of an electromotive force (i.e., voltage) across an electrical conductor due to its dynamic interaction with a magnetic field. Induction is used in power generation and power transmission, and it’s worth taking a look at how that’s done. There are other effects with some interesting applications to consider, too, such as eddy currents. An Electric Generator – An electric motor is a device for transforming electrical energy into mechanical energy; an electric generator does the reverse, using mechanical energy to generate electricity. At the heart of both motors and generators is a wire coil in a magnetic field. The same device can be used as a motor or a generator. Eddy Currents – An eddy current is a swirling current set up in a conductor in response to a changing magnetic field. Transformers – Electricity is often generated a long way from where it is used and is transmitted long distances through power lines. ACTIVITIES Activity 1 – Induced EMF & Induced Current Using the galvanometer and the description of the movement of the magnet, write and explain your observations based on the galvanometer reading on the space provided: Illustra+on Descrip+on The magnet is moved through a coil of wire. (Photo Credits: Google Image) The magnet is moved faster through the coil of wire. (Photo Credits: Google Image) Loops of wire were added (Photo Credits: Google Image) The magnet is pulled out rather than pushed in (Photo Credits: Google Image) Observa+on/s Activity 2 – Practice Problems Apply Faraday’s Law of Electromagnetic Induction in solving word problem/s. 1. A coil with 25 turns of wire is wrapped around a hollow tube with an area of 1.8 m2. Each turn has the same area as the tube. A uniform magnetic field is applied at a right angle to the plane of the coil. If the field increases uniformly from 0.00 T to 0.55 T in 0.85 s, find the magnitude of the induced emf in the coil. If the resistance in the coil is 2.5 Ω, find the magnitude of the induced current in the coil. 2. A coil consists of 200 turns of wire having a total resistance of 2.0. Each turn is a square of side 18 cm, and a uniform magnetic field directed perpendicular to the plane of the coil is turned on. If the field changes linearly from 0 to 0.50 T in 0.80 s, what is the magnitude of the induced emf in the coil while the field is changing? What is the magnitude of the induced current in the coil while the field is changing? WRAP -UP Complete the table about what you have learned about this module: VALUING/APPLICATION POWER TRANSMISSION: Power transmission uses transformers to increase voltage for long-distance transmission and decrease it before it reaches your home. Why is almost all electrical energy sold today in the form of alternating current? Copyright © : PresentationExpress Conceptual Physics POSTTEST Choose the letter of the best answer. Write the chosen letter in your notebook. 1. What is electromagnetic induction? A. The production of an electric current created by a varying magnetic field B. The production of the magnetic field, accomplished by running a current through a coil of wire C. Creating electromagnetic fields by any purposeful means D. Building a magnet 2. If a wire is moved perpendicular to the magnetic field, what is induced across the ends of the wire? A. area B. coil C. magnetic field D. potential difference 3. All matters are said to be neutral wherein the numbers of electron and protons are equal so once charges it do not stay for a long time because of the following factors except; A. faster B. slower C. in opposite direction D. parallel to the magnetic field 4. the amount of induced potential difference can be increased if the wire is moved in the magnetic field ___________ A. generating electricity B. energy efficient cookers and burners C. energy-efficient motors D. using a magnet to separate scrap metal parts 5. Which of the following is NOT a way that a magnetic field can be varied to induce a current in a wire? A. Move the coil in and out of the magnetic field B. Rotate the coil inside the magnetic field C. Move the coil once it is already fully inside the magnetic field D. Change the strength of the magnetic field R E F E R E N CE S Physics by Holts, Rineheart and Winston, Electromagnetic Induction, Chapter 20 Serway, Physics 5th Edition PDF Presentation Express, Conceptual Physics, Electromagnetic Induction, Chapter 37. https://www.assignmentpoint.com/science/physics/electromagneticinduction.html https://phet.colorado.edu/sims/cheerpj/faraday/latest/faraday.html?simulation= generator