1. Electromagnetic Induction Colby, Heston, Nathan, Elizabeth, Joseph

2. Presentation

3. State and Explain Major Concepts The major concepts for chapter 37 Electromagnetic Induction are electromarnetic induction, Faraday's law, generator and transform. Electromagnetic Induction is the phenomenon of including a voltage in a conductor by changing the magnetic field around the conductor. Faraday's law is the statement that the induced voltage in a coil is proportional to the product of the number of loops and the rate at which the magnetic field changes within those loops. In general, the statement that an electric field is induced in any region of space in which a magnetic field is changing with time. The magnitude of the induced electric field is proportional to the rate at which the magnetic field changes. A generator is a machine that produces electric current by rottating a coil within a stationary magnetic field. A transformer is a device for increasing or decreasing voltage by means of electromagnetic induction.

4. Historical Perspective In the early nineteenth century the discovery that magnetism could be produced with electrical wires was a turning point in physics and the technology that followed. In 1831 Michael Faraday and Joseph Henrys discovery was to make electricity so common that it could power industries by day and light up cities by night. Faraday and Henry discovered that electric current could be produced in a wire by simply moving a magnet in or out of a wire coil (Conceptual Physics, 554). Hewitt, P. G. (1998). Conceptual physics (Vol. P. 554). Reading, MA: Addison Wesley.

5. Application of Concepts Electromagnetic induction is used in many different types of electrical devices. The main devices that electromagnetic induction is used in is in electric generators and electric motors. The generator and motor both contain a magnetic field with a coil. The magnetic field interacts with a current that spins the coil in a motor and the coil is spun which induces a current in the coil in a generator. These magnetic fields and the interactions they cause are induced by electromagnetic induction (Physics. Boston University). "Applications of Electromagnetic Induction." Physics. Boston University, 22 July 1999. Web. 2 Feb. 2016.

6. Think and Explain Questions 1. The amount of current induced in a loop of wire increases or decreases based on the frequency of an oscillating magnetic field. 2. A generator armaure is more difficult to rotate when it is connected to and supplying electric current to a circuit because when the magnetic fields of two magnets overlap, the two magnets are either forced together or apart. When one of the fields is induced by the motion of the other, the polarity of the fields is always such as to force them apart, causing the resistance you feel. 3. Yes, because it doesn’t need to generate the power for the lamp. 4. The transformer requires alternating voltage because it needs to change the voltage going out to be lower than the voltage coming in. 5. Yes. because if a wire is looped around the magnet 2 times, the receiving end will receive twice as much voltage, and to make the voltage go even higher, they can add even more loops. 6. The secondary should have 50 turns. 7. 12 volts will power the train. 8. The ratio of Primary turns to Secondary turns is 12:0.0005 9. Yes, the magnetic field will be altered, and it will produce a current pulse. There is not really a practical application of this. 10. For the motor to power the generate to begin with, it would need fuel, and since there is no fuel, the cycle wouldn’t begin at all.

7. Review Questions 1. Michael Faraday and Joseph Henry discovered a better way to create electricity. 2. Voltage can be induced in a wire by moving the wire in and out of a magnetic field. 3. More loops in the coil will produce more voltage. 4. It is more difficult to push a magnet through more loops of wire because each loop becomes an electromagnet that resists the magnetic. 5. The voltage generated is equal across different materials, but the current changes. 6. The frequency of the induced alternating voltage is equal to the frequency of the changing magnetic field within the loop. 7. A generator is a motor running backwards, it rotates the coil in a stationary magnetic field. 8. The voltage induced by the generator alternates because as the loop rotates the magnitude and direction of the induced voltage change. 9. A turbine on the outside of a generator is rotated by wind or water. 10. Magnetic force, magnetic field, and moving charges. 11. The magnetic field that builds up around the primary extends to the secondary coil. Changes in the magnetic field of the primary are sensed by the secondary coil nearby the changes of magnetic field intensity at the seconday induce voltage. 12. The alignment of magnetic domains in the iron intensifies the magnetic field around the primary, which extends to the secondary which as a results in the secondary interceoting more of the field change. 13. Transformers transform voltage and current, but not electricity. 14. A step up transformer steps up voltage. 15. The more turns the more voltage produced, the less turns the less voltage. 16. 60 volts 17. a. The power input into the primary coil is the same as the power output of the second coil. b. The product of current and voltage are the same in the primary and secondary coils 18. It is advantageous because less energy is lost through heating the wires. 19. Electric Fields 20. Faradays Law electricity is produced by moving magnetism Maxwell's Law is magnetism produced by moving electricity so they are exact opposites of each other 21. The higher the speed of the fields emanation the greater the magnitude of the field that is induced, and vice versa for low speed emanation. 22. Electromagnetic waves with a frequency between 400 - 700 nm.

8. Demostration

9. Background Information When a magnetic field has a changing intensity that is perpendicular to a wire will induce a voltage along the length of that wire. The amount of voltage induced depends on the rate of change of the magnetic field flux and the number of turns of wire exposed to the change in flux. Only if the wire is coiled. Faraday’s equation for induced voltage is e = N(dΦ/dt). A current-carrying wire will experience an induced voltage along its length if the current changes thus changing the magnetic field flux perpendicular to the wire, thus inducing voltage according to Faraday’s formula. A device built specifically to take advantage of this effect is called an inductor (Electromagnetic induction, Ch.14). If two coils of wire are brought into close proximity with each other so the magnetic field from one links with the other, a voltage will be generated in the second coil as a result. This is called mutual inductance: when voltage impressed upon one coil induces a voltage in another. A transformer is a device specifically designed to produce the effect of mutual inductance between two or more coils(Electromagnetic induction, Ch.14). Mutual Inductance. (n.d.). Retrieved February 03, 2016, from http://www.allaboutcircuits.com/textbook/direct-current/chpt-14/mutual- inductance/

10. Question or Hypothesis Question: What items will create induced voltage when they passes through a coil of wire? Hypothesis: We hypothesize that non magnetic materiel won't create induced voltage and only the magnet will create induced voltage.

11. General Statement of How You Will Conduct the Demonstration We will first collect all materiel needed then we will take each of the items and pass them through the coil of wire to see if they produce induced voltage starting with the magnet then pencil, then paper, then pen, then flash drive, then the meter stick and finally the pair of scissors and record all of your data.

12. Apparatus and Materials 1) Coil of wire 2) Connecting wire 3) Galvanometer 4) Magnet 5) Pencil 6) Paper 7) Pen 8) Flash Drive 9) Meter Stick 10) Scissors

13. Step-by-Step Instruction for Doing the Demonstration 1) Collect all materiel and set up the experiment 2) Take the magnet and pass it through the coil of wire record if the galvanometer registers induced voltage. 3) Take the pencil and pass it through the coil of wire record if the galvanometer registers induced voltage. 4) Take the paper and pass it through the coil of wire record if the galvanometer registers induced voltage. 5) Take the pen and pass it through the coil of wire record if the galvanometer registers induced voltage. 6)Take the flash drive and pass it through the coil of wire record if the galvanometer registers induced voltage. 7) Take the meter stick and pass it through the coil of wire record if the galvanometer registers induced voltage. 8) Take the scissors and pass it through the coil of wire record if the galvanometer registers induced voltage.

14. Safety Precautions Be careful to not run with scissors and when walking keep it facing away from your body.

15. Collecting and Presenting Data The ItemIf it is Capable of Producing Induced Voltage MagnetYes (Large Amount) Pencil No Paper No Pen No Flash DriveNo Meter StickNo ScissorsYes (Small Amount)

16. Analysis of Results All the items that we tried showed no amount of voltage other than the magnet and the scissors. The magnet had a very high voltage count and the scissors had a very low amount.

17. Conclusion Supported by Evidence In conclusion our hypothesis must be rejected due to the slight amount of voltage shown with the scissors. Otherwise it would be correct but because we were slightly off it is incorrect.

18. Evaluation of Your Hypothesis Our hypothesis is wrong because when we tested the scissors they showed voltage and we hypothesized that there would be no amount of voltage in any materials other than the magnet.