40235411 ohm

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40235411 ohm

  1. 1. R e p u b l i c o f th e P h i l ip p in e s Department of EducationRegion VII, Central Visayas D i v i s i o n o f M an d a u e C i t y OHM’S LAW Prepared by:JOEMIL REY BOLAMBAO IV – Descartes KEVIN JAY MABUTI IV – Descartes Submitted to: MRS. EVELYN LAURON Physics Teacher
  2. 2. I. Title PageII. Table of ContentsIII. Guide CardIV. IntroductionV. Activity Card #1VI. Activity Card #2VII. Assessment Card #1VIII. Enrichment Card #1IX. Enrichment Card #2X. Answer CardsXI. Reference Card
  3. 3. BOOKS Giancoli, Douglas C. (1995). Physics: Principles with Applications (4th ed ed.). London: Prentice Hall. ISBN 0-13-102153-2. John OMalley, Schaums outline of theory and problems of basic circuit analysis, p.19, McGraw-Hill Professional, 1992 ISBN 0070478244INTERNET http://en.wikipedia.org/wiki/Ohm’s_Law http://www.petsdo.com/blog/Origin_of_Ohm’s_Law http://en.wikipedia.org/wiki/Resistivity http://www.physicslab.com/Ohms%20%Law
  4. 4. Olah Amigos! Olah Boots! I am SIMDORA, the knowledge explorer. Today, we will be going into another fun and exciting adventure as we journey in the world of science. We will know more about the Ohm’s Law.What is Ohm’sLaw? This Strategic Intervention Material (SIM) is designed to give you a wide understanding regarding Ohm’s Law. After going through this SIM, the reader is expected to: Define and state the Ohm’s Law Identify the relationship of Voltage, Current and Resistance Solve problems involving the relationship of Voltage, Current and Resistance Apply Ohm’s Law in practical situations. Now that you know what we will be encountering, here is a short review about the topic.
  5. 5. Olah Amigos! I heard the Boots doesn’t exactly know what Ohm’s Law. To know more about it we will be going to the house of Mr. George Simon Ohm. To get there, we must pass the brain maze, down to the Electric Castle and Then to Mr. Ohm’s House. Remember, Maze, Castle, Ohm’s House. Say it with me. Maze, Castle, Ohm’s House.....Ohms law states that the current through a conductor between two points isdirectly proportional to the potential difference or voltage across the two points, andinversely proportional to the resistance between them.The mathematical equation that describes this relationship is: where I is the current through the resistance in units of amperes, V is the potential difference measured across the resistance in units of volts, and R is the resistance of the conductor in units of ohms. More specifically, Ohms law states that the R in this relation is constant, independent of the current. The law was named after the German physicist Georg Ohm, who, in a treatise published in 1827, described measurements of applied voltage and current through simple electrical circuits containing various lengths of wire. He presented a slightly more complex equation than the one above to explain his experimental results. The above equation is the modern form of Ohms law.
  6. 6. Let’s went to Mr. George Ohm’s House. Where should we gofirst? Do you know where should we go first?The Brain Maze, right. Will you help me cross the brain maze?Thank you! Now let’s go cross the maze!Activity 1: THE BRAIN MAZEStart A D G H C I B E K F L J End These little brain monsters won’t let you pass unless you defeat them by answering their questions. Select your answers from the answer pool. A. The potential difference measured across the resistance. B. Who pioneered the study on the relationship of current, voltage and resistance? C. Unit of measurement for current. (D)____ states that the current through a (E)____ between two points is (F)____ proportional to the (G)_______ difference or voltage across the two points, and (H)_____ proportional to the resistance between them. I. Unit of measurement for resistance. J. The mathematical equation of the relationship of current, voltage and resistance. K. A device use to measure current. L. It is the measure of how much current can flow through a component. Ohm’s Law Ammeter Ampere Directly Voltage V I= George Ohm R Ohm Potential Inversely Resistance Conductor
  7. 7. We’ve made it through the brain maze. Now we’re heading towards the castle. My friend told me that the castle’s door will only open if you can close all its windows. Will you help me close the windows?Activity 2. The Electric Castle’s Entrance To open the door of the Castle, we must close all itswindows, but the problem is that every window may only beclosed by the exact current, resistance and voltage of itscircuit. Complete the table below to close the windows andopen the Door of the Castle. The castle has 13 windows. Window Number Voltage Current Resistance 1 15 volts 30 amperes ___ ohms 2 21 volts ___ amperes 3 ohms 3 220 volts 20 amperes ___ ohms 4 ___ volts 30 amperes 15 ohms 5 110 volts ___ amperes 10 ohms 6 3 volts 12 amperes ___ ohms 7 ___ volts 50 amperes 25 ohms 8 15 volts 30 amperes ___ ohms 9 ___ volts 21 amperes 7 ohms 10 120 volts 30 amperes ___ ohms 11 6 volts ___ amperes 15 ohms 12 ___ volts 30 amperes 10 ohms 13 ___ volts 30 amperes 5 ohms
  8. 8. Welcome to my Castle! I’ve heard that you gone along an electrifying journey. Let’s see what you have learned. Here are my little playing circuits. My friends will help me in playing with your circuits.Activity 2. Playing With CircuitsSolve the following circuit problems. Zeus might help you inyour journey.1. An emf source of 6.0V is connected to a purely resistivelamp and a current of 2.0 amperes flows. All the wires areresistance-free. What is the resistance of the lamp?The current flowing in a circuit containing four resistorsconnected in series is I = 1.0 A. The potential drops across thefirst, second and third resistors are, respectively: V = 5 V, V = 8V and V = 7 V. The equivalent resistance of the circuit is R = 30 . (Hint: Resistors connected in series have the same current flowsthrough each one.)2-5. Resistance of each resistor in the circuit R1, R2, R3 & R46. Voltage drop on the fourth resistor.7. Find the total voltage supplied by the battery8-10. (3 points) In the following schematic diagram, find thetotal current, I.(Hint: Currents through branches of a parallel circuit add to give thetotal current and Voltage in each resistor is the same as the totalvoltage.) Very Clever! As a reward, I’ll use my power to transport you directly inside the house of Mr. Ohm.
  9. 9. We did it! We made through the house of Mr. Ohms but it looks like he is not here so let’s just explores his place and learn more about Ohm’s Law.Ohms Law defines the relationships between (P) power, (E) voltage, (I) current, and (R)resistance. One ohm is the resistance value through which one volt will maintain a currentof one ampere.(I) Current is what flows on a wire or conductor like water flowing down a river. Currentflows from negative to positive on the surface of a conductor. Current is measured in (A)amperes or amps.(E) Voltage is the difference in electrical potential between two points in a circuit. Its thepush or pressure behind current flow through a circuit, and is measured in (V) volts.(R) Resistance determines how much current will flow through a component. Resistors areused to control voltage and current levels. A very high resistance allows a small amount ofcurrent to flow. A very low resistance allows a large amount of current to flow. Resistanceis measured in ohms.(P) Power is the amount of current times the voltage level at a given point measured inwattage or watts.
  10. 10. I am sure that your brain is going short circuit rightnow. Let’s relax and look back to the history of Ohm’sLaw. The Origin of Ohms Law Georg Simon Ohm was born in Bavaria in 1789. His father taught him philosophy, chemistry, mathematics and physics. In 1806 he became a mathematics teacher in Switzerland. In 1811 he received a doctorate from Erlangen and became a mathematics lecturer there. In 1817 he took a position as professor of mathematics and physics at the Jesuit Gymnasium of Cologne. In 1820 he learned of Oersteds electromagnetism discovery and began experimenting with electricity in the schools physics laboratory where he convinced himself of what is now known as Ohms law. In 1825 he published a paper that explains the decrease in electromagnetic force (which is proportional to current) around a wire as its length is increased. He published two papers in 1826 that mathematically describe electrical conduction in circuits. In 1827 he published his famous book Die Galvanische Kette, mathematisch bearbeitet, which contains what we now know as Ohms law. His theories were scorned at the time and he was forced to resign his teaching position because of them.
  11. 11. (Assessment)1. An emf source of 6.0V is connected to a purely resistive lamp and a current of 2.0 amperesflows. All the wires are resistance-free. What is the resistance of the lamp?The gain of potential energy occurs as a charge passes through the battery, that is, it gains apotential of =6.0V. No energy is lost to the wires, since they are assumed to be resistance-free. By conservation of energy, the potential that was gained (i.e. =V=6.0V) must be lost inthe resistor. So, by Ohms Law: V=IR R=V/I R = 3.02-7. The current flowing in a circuit containing four resistors connected in series is I = 1.0 A. Thepotential drops across the first, second and third resistors are, respectively: V = 5 V, V = 8 V andV = 7 V.The equivalent resistance of the circuit is R = 30 . 2-5. Resistance of each resistor in the circuit R1, R2, R3 & R4 6. Voltage drop on the fourth resistor. 7. Find the total voltage supplied by the battery Hints 1. How are resistors related when connected in series? 2. What is true about potential drops of resistors when connected in series? 3. You will need to use Ohms Law.
  12. 12. Solution First, lets label the diagram with the information given in the question. There are several ways of solving this problem (see alternate solutions), but this tutorial will only go through one of these ways.Because the resistors are connected in series, then the same current flows through each one.Using the Ohms Law, we can find the resistances of the first, second and third resistors. Now, using the equivalent resistance, we can find the resistance in the fourth resistor. This is a series circuit, so the equivalent resistance is the sum of the individual resistances. The current flowing through the fourth resistor is also I=1.0A. Using Ohms Law again, we find the voltage across this resistor. The total voltage supplied by the battery must equal to the total voltage drop across the circuit (this is known as Kirchhoffs Voltage Law). So, we must sum up the voltage drops across the resistors.
  13. 13. (8-10) In the following schematic diagram, find the total current, I.You will need Ohms Law. 1. How are resistors related when connected in parallel? 2. What is the potential drop across each resistor? 3. How does current behave in parallel branches?SolutionWe know the total potential of this circuit, = 12.0 VSo, between points A and B, the potential must drop 12.0V. Also, the potential dropacross branches of a circuit are equal. That is,We can use Ohms Law V = IR or I = V/Rto find the current across each resistor. Recall that the currents through branches of a parallel circuit add to give the total current. That is, the total current splits up so that part of the total current travels down each branch. Because of conservation of charge, the sum of the currents in each branch must equal the amount going into the branch. (This is Kirchhoffs Current Law.) So, adding up the three currents, we get: So, the total current is I = 12.0A.
  14. 14. Activity 2. The Electric Castle’s Entrance To open the door of the Castle, we must close all its windows, but theproblem is that every window may only be closed by the exact current, resistanceand voltage of its circuit. Complete the table below to close the windows and openthe Door of the Castle. The castle has 13 windows. Window Number Voltage Current Resistance 1 15 volts 30 amperes 0.5 ohms 2 21 volts 7 amperes 3 ohms 3 220 volts 20 amperes 11 ohms 4 450 volts 30 amperes 15 ohms 5 110 volts 11 amperes 10 ohms 6 3 volts 12 amperes 0.25 ohms 7 6250 volts 50 amperes 25 ohms 8 15 volts 30 amperes 0.5 ohms 9 147 volts 21 amperes 7 ohms 10 120 volts 30 amperes 4 ohms 11 6 volts 0.4 amperes 15 ohms 12 300 volts 30 amperes 10 ohms 13 150 volts 30 amperes 5 ohms In completing the table above we use the following formula. For Voltage: V = I x R For Current: I = V / R For Current: R = V / I
  15. 15. Activity 1: THE BRAIN MAZEStart A D G H C I B E K F L J End These little brain monsters won’t let you pass unless you defeat them by answering their questions. Select your answers from the answer pool. A. Voltage is the potential difference measured across the resistance. B. George Simon Ohm pioneered the study on the relationship of current, voltage and resistance. C. Ampere is a unit of measurement for current. (D) Ohm’s Law states that the current through a (E) Conductor between two points is (F) Directly proportional to the (G) Potential difference or voltage across the two points, and (H) Inversely proportional to the resistance between them. I. Ohm is a unit of measurement for resistance. J. The mathematical equation of the relationship of current, voltage and resistance is K. Ammeter is a device use to measure current. L. Resistance is the measure of how much current can flow through a component.

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