# Electricity Simplified

Size: px
Start display at page:

Transcription

1 Electricity Simplified 0 people liked this 0 discussions READING ASSIGNMENT Electrical Circuits An electrical circuit is defined as a complete electrical path. A typical circuit includes four components: The power source feeds power into the circuit. In homes, the power source is the service panel. The conductors are the wires that carry the electricity. The load is any device, such as a light fixture or appliance, that runs with electricity. The switch is the device used to turn the electricity flow on and off. In a circuit, when the switch is turned on, electrical current from the power source flows through an unbroken path to the load. Then, the light turns on or the appliance runs. This is called a closed circuit because the circuit is complete the current flows through the entire circuit path. When the switch is turned off, the path of the circuit is broken, and the current can t flow to the load. The light goes out or the appliance stops running. This is called an open circuit. This figure illustrates a simple electrical circuit. In A, the switch is open, so electricity can't flow to the lightbulb. In B, the switch is closed, allowing electricity to reach the lightbulb. 1/14

2 A simple flashlight circuit is shown in the figure. The power source in this circuit is a battery. The conductors are copper wire. The load is a standard light bulb. In A the switch is open (turned off). The electrical circuit is therefore open, and current can t flow through the wires to get to the lightbulb. In B the switch is closed (turned on). The circuit is therefore complete, and current can flow through the wires to reach the lightbulb and turn it on. Electrons Did you ever wonder what electricity really is? In simple terms, electricity is the movement of electrons. All matter in the universe is formed from about 100 or so different substances called elements. An atom is the smallest particle of an element that retains the properties of the element. So, each different element, such as gold, silver, or oxygen, is made up of its own unique gold, silver, or oxygen atoms. All atoms are made up of tiny atomic particles called protons, neutrons, and electrons. The electron is a tiny, very lightweight particle that has a negative electrical charge. Protons are much heavier than electrons, and they have a positive charge. Neutrons have no electrical charge at all they re neutral. Electrons are the smallest type of atomic particle; they re much smaller than the atom as a whole. A single atom of hydrogen contains one proton and one electron. The proton is represented by the circle with the plus sign (+) inside. The electron is represented by the circle with the minus sign (-) inside. 2/14

3 A copper atom contains a single electron in its outermost orbit. This free electron can be easily dislodged from its orbit. Both silver and copper atoms have a free electron in their outermost orbits, and both are good electrical conductors. However, the free electron in the silver atom is farther away from the nucleus than the free electron in the copper atom. This means that the silver electron can be more easily dislodged from its orbit than the copper electron. Thus, silver is an even better electrical conductor than copper. 3/14

4 A hydrogen atom is the simplest atom, as it contains one electron and one proton. The proton is located in the nucleus, or the center, of the atom. The electron orbits around the nucleus, much as the moon orbits around the earth. All atoms are constructed in the same general way as the hydrogen atom, but the number of protons, neutrons, and electrons varies with each different substance. The hydrogen atom is perfectly balanced electrically. The atom contains one positively charged proton and one negatively charged electron; the proton and electron balance each other out. Because of this balance, the electron in a hydrogen atom is tightly attached to the proton. The electron can t be easily removed from the atom. Now, look at an atom of copper. The copper atom contains 29 electrons and 29 protons. The electrons orbit the nucleus of the copper atom in several layers called shells. The outermost shell contains only one electron called a free electron or valence electron. Since the free electron is alone and very far away from the atom s nucleus, it can be easily dislodged from its orbit. Free electrons that can be easily dislodged from their orbits are very important in your study of electricity. You ve learned that electricity (electrical current) is produced by the movement of electrons. To get the electrons moving, they have to be removed from their atoms. The structure of an atom will determine how easily an electron can be removed from it. For example, you saw that the structure of the hydrogen atom makes it difficult to remove an electron from its orbit. Because of this, it s very difficult to get electrons moving in hydrogen atoms. However, in the copper atom, the outermost electron can be easily removed from its orbit. Therefore, it s very easy to produce a flow of electrical current in copper atoms. This is why copper is used in electrical wires and cables. Any substance in which electrons can move freely is called a conductor. Atoms that are tightly bonded are very poor conductors of electricity, while atoms that contain free electrons in their outer shells (like copper) are excellent conductors of electricity. Conductors and Insulators When electrical current is applied to different materials (such as metals or plastics), it may or may not be carried readily. A material in which electrons can be moved easily from one atom to another is a good conductor because it conducts (carries) electricity. Metals like copper, silver, and aluminum readily allow electricity to flow through them and are, therefore, good conductors. In contrast, a material in which electrons can t be moved easily from their atoms is a poor conductor of electricity. Some materials carry almost no electricity at all, even when a very high voltage is applied to them. These materials are called insulators because they re insulated against electrical flow. Examples of insulators are glass, mica, porcelain, paper, plastic, and rubber. The properties of conductors and insulators are important because they have practical applications in home electrical systems and in electrical devices and equipment. Metals like copper and aluminum are used in electrical wiring because they carry electrical current so well. Insulating materials like plastic and rubber are used as coatings on the outside of cables to prevent the current from leaking out. Positive and Negative Charges The behavior of positive and negative charges is very similar to the behavior of the two poles a magnet. You know that in magnets, the opposite poles attract each other, and the same poles repel each other. So, if you hold the opposite poles (north and south) of two magnets close together, the poles will stick together. If you hold the same poles (north and north or south and south) of two magnets close together, the poles will push each other away. The magnets create what's known as a magnetic field. 4/14

5 In the same way, atomic particles that are electrically charged will attract and repel each other. The electrical charges create what's known as an electric field which has similar attract and repel properties as a magnetic field. When a large number of electrons are together, all of their negative charges cause the electrons to repel each other strongly. As a result, electrons can t touch together. Only their charges interact with each other, keeping each electron away from the other electrons. In a copper wire, there are billions of loose or free electrons, all safely in place in their orbits. They re distributed evenly throughout the wire. When a large number of electrons are together, all of their negative charges cause the electrons to strongly repel each other. As a result, the electrons can t touch together. Their charges interact with each other, pushing each electron away from the other electrons. Electrons in Motion If you can get one electron in a wire to move, the repulsion of the negative charges will start other electrons moving. Instantly, a chain reaction begins, with billions of electrons repelling each other and moving through the wire. The electrons all move in the same direction. 5/14

6 When electrons are forced to move, they become a current flow and are able to perform work. The electrons move in a chain reaction. One electron bumps into another, and that electron bumps into another, and so on, with each electron bumping the next one in line. 6/14

7 As each moving electron strikes and repels the next electron in the chain, some energy is lost. The lost energy is felt as heat in the wire. The kinetic energy associated with the electrical current can be converted to perform useful work. (In other words, the energy can be used to run lighting fixtures and appliances.) Remember, though, that to do work, electrons have to be in motion. When they stand still, they do no work. The electrons will be moved to work whenever you turn on a light switch or plug in an appliance. Direct and Alternating Current When electrons move in one direction, the resulting current flow is called direct current, or DC. Direct current is produced mainly by storage batteries and is used in battery-operated equipment and devices (such as flashlights, automobiles, and cordless tools). When electrons move in both directions, the current flow is called alternating current, or AC. In AC, the electrons start off in one direction, stop, reverse themselves, and go back in the opposite direction. Work is performed whenever the electrons are moving, no matter which direction they move in. In the United States, the electricity used in typical home circuits is alternating current. Alternating current changes its direction at a frequency of 60 cycles per second. This means the electrons flow first in one direction, then in the reverse direction, repeating this cycle 60 times every second. The frequency of electron movement is measured in units called hertz; one cycle per second is equal to one hertz, abbreviated 1Hz. Voltage Now that you understand how electrons move in a conductor, you may be wondering how they begin to move. Electrons can be forced to move when more electrons are pushed into the wire. The pressure required to force electrons into a wire is called voltage or electromotive force. Voltage is measured in units called volts (abbreviated V). When voltage (electrical pressure) is applied to a wire, the loose electrons are packed under pressure. Voltage, or electrical pressure, is always present in wall receptacles. However, work is done only when voltage moves electrons through a circuit. For this current to flow, the circuit must be complete. Remember, electrons can t flow into the wire without having a way to get out at the other end. So, suppose that you plug a lamp into a wall receptacle. Electrons from the voltage source will force their way into the lamp wire. The electrons will move through the wire, through the filament of the lightbulb, and out through the other wire. In the United States, electricians work with several common voltages 120/240 V, 120/208 V, and 277/480 V are the most common. A typical home will work with either 120 V or 240 V. In a wall receptacle for a lamp, the typical voltage is 120 V. Most electrical devices and appliances are designed to 7/14

8 operate with the 120/240 V that s supplied by local electric utility companies. Higher voltages are used for much larger appliances and things like machinery and industrial equipment. Measuring Current Flow To form an image of current flow in your mind, take a moment to think about a water system. In order for water to flow through a piping system, it must have somewhere to go. If you try to push water into a pipe that s already filled with water and blocked on one end, no new water will be allowed to enter the pipe. If you remove the blockage by adding a drain to the pipe, the water will flow as long as the pressure remains in the system. Electricity acts similarly to a water system; it must have pressure to push it along, and a drain to allow it to flow continuously. Current needs a push to get its flow started. This push comes from voltage. In our water system example, the water pressure can be compared to voltage. The greater the water pressure, the greater the flow of water will be through the pipes. In the same way, the greater the voltage applied to a circuit, the greater the flow of electrons in the circuit. Current flow in a circuit is maintained by a constant, or uninterrupted, voltage. Voltage or electrical pressure forces electricity to flow. The amount of electric current flowing through a circuit is called amperage. The amount of current is measured in units called amperes or amps (abbreviated A). One ampere of current is equal to the charge of 6,240,000,000,000,000,000 electrons flowing past a given point in a circuit per second. The rate of electron flow determines the number of amperes in a circuit. You can see that it takes many millions of electrons flowing in a circuit to perform useful work! Current flow or amperage can be measured with a device called an ammeter. The ammeter measures the rate of electron flow that passes through a cross section of wire. 8/14

9 The electrical current flow or amperage that can be measured with an ammeter is the rate of electron flow that passes through a cross section of wire. In our water system example, the current could be compared to the volume of water that s flowing through the water system in a given amount of time (for example, the number of gallons per minute that are flowing through the system). Water can flow more easily through the system if a large pipe is used instead of a small one. Similarly, in an electrical system, resistance to the current can be decreased by using thicker conducting wires. Using Current to Perform Work Once electrons are moving in a wire, they can be used to perform work. This is because as current flows, it possesses kinetic energy which can be converted to heat energy, light energy, or other forms of motion by devices in the home. For example, when current passes through a light bulb filament, the filament gets white-hot and emits light. When it passes through a toaster s heating element, the element gets red-hot and transmits heat to your bread. Current passing through a motor s field coils generates a magnetic field that makes the motor rotate, producing mechanical power. 9/14

10 Electrical energy is used to produce heat (in a toaster or space heater), to provide mechanical energy or motion (in fans and motors), and to provide light in a home. Different devices need different amounts of electrical current to operate. Each device requires a certain number of amps. Therefore, the electrical system in a home is designed to handle your total amperage needs. If you add up all the amps you need to run your home, you ll probably find that you use less than 200 A. For example, your air conditioner may require between 15 A and 20 A, but your television may need only 1 A to 2 A. When an electrical system is installed, the system must be designed to handle the home s total amperage needs. This total is calculated assuming that all appliances are turned on at the same time. The amount of amperage required varies depending on the type of electrical device. Since more amps often means higher costs, many of today s appliances and other electrical devices are designed to use less amperage and thus be more energy efficient. A typical home electrical system will operate with 120/240 V. The 120/240 V voltage that a typical home uses comes from the power company and remains the same at all times. In most cases, the power company has the ability to provide you with all the power you require. The amount of current 10/14

11 that s used varies, however, as different appliances are turned on and off. As more devices are turned on, more current flow is needed to pass through the electrical system. Electrical Units At this point in your studies, it will be helpful to review some of the standard units, notations, and symbols used in electrical work. In the field of electricity, a variety of terms are used to describe quantities in electrical components and circuits. Some of these units are volts, amps, coulombs, ohms, and watts. Electrical Units Quantity Unit Definition of Basic Unit Potential Volt (V) One volt is the work of one joule per coulomb. Current Ampere (A) One ampere is the movement of electrical charges at a rate of 1 coulomb per second. Charge Coulomb (C) One coulomb is the quantity of charge equal to electrons. Resistance Ohm (Ω) One ohm is the resistance that allows a current of one ampere when a potential of one volt is applied to a conductor. Power Watt (W) One watt is the power exerted in a circuit with a potential of 1 volt and a current of 1 ampere. You ve already learned a little bit about volts and amps. The strength of electromotive force is measured in volts. Voltage can be compared to water pressure in a water system. The stronger the voltage, the stronger the flow of electrons in an electrical circuit. Amperage refers to the amount of electric current flowing through a circuit and is measured in amperes, or amps. Electrical resistance is the opposition that a circuit creates against the flow of electrical current. The magnitude of electrical resistance in a circuit is measured in ohms. One ohm is equal to the resistance of a circuit in which one volt is applied to produce one ampere of current. The abbreviation used for ohm is the symbol Ω. Another electrical unit you should be familiar with is the watt. Watts are used to measure power, or the amount of useful work that can be done by a circuit. The abbreviation for watt is W. How Electrical Units Are Related Three of the electrical units just discussed have a special relationship to one another. These three units are the ohm, the ampere, and the volt. The connection between these units was first defined by George Ohm, and his statement of this relationship is called Ohm s law. 11/14

12 If we use the letters V, I, and R to represent voltage, current, and resistance, we can state Ohm s law with the formula V = I R in which V stands for voltage in volts, I stands for current in amperes, and R stands for resistance in ohms. Note that in Ohm's Law, the letter I stands for current. This is derived from the French phrase intensité de courant, or current intensity in English. "Current intensity" has since been shortened to simply "current" in modern terms. It's important to remember that I stands for current, but a measurement of current will be given in amperes, or A. In your work with electricity, Ohm s law will have many practical applications. Using the Ohm s law formula and a little basic math, you can determine the voltage, current, or resistance in any circuit. Watts So far, you've learned about the flow of current in the system, which is measured in amperes. As a homeowner, you pay the electric company for the amount of current flow you use from its wires. The more current you use, the higher the electric bill. When looking at a typical bill, you may think that the rate the power company charges for electricity is based on amperes. However, it s actually based on a different measurement kilowatts. To understand kilowatts, think of the way light bulbs are labeled. Bulbs are typically marked with their wattages, or W for example, 60 W or 100 W. The watt is the basic unit that s used to measure electrical power. So, the watt label on a lightbulb is the amount of power that s required to light that particular bulb. Unlike amperage, which is a measure of the amount of flow, power is a measure of how much work can be done by the flow over a period of time. Since one watt of power is a very small amount, power is commonly measured in kilowatts (kw). One kilowatt is equal to 1,000 watts. Every device in a home uses a certain amount of power when it s turned on. Electrical power is the product of the voltage and the current in a circuit. That is, voltage (in volts) multiplied by current (in amperes) equals power (in watts). This relationship is expressed by the following formula: P = V I In this formula, V stands for voltage in volts, I stands for current in amperes, and P stands for power in watts. However, note that you don t pay the electric company for power; you pay for energy. Energy is the amount of power that s used over a period of time. The unit that s commonly used to measure electrical energy is the kilowatt-hour (abbreviated kwh). One kilowatt-hour is equal to one kilowatt of power taken continuously from the utility for a period of one hour (h). Your bill from the electric company is calculated according to the number of kilowatt-hours of energy used. The amount of energy used in your home is measured by an electric meter that s called a kilowatt-hour meter. In previous times, an electric company employee read the kilowatt-hour reading on your electric meter to determine how much energy you had used, and thus how much you must pay the electric company. Today all new kwh meters are either connected to the utility by modem or through the power line itself using a technology known as Power Line Communication (PLC). The wattage of an appliance is the amount of power that s needed to enable the appliance to function properly, as observed earlier with the lightbulbs. Look at the list of appliances in the Appliance Power Ratings table. The table lists the wattage of several popular appliances. If all of these appliances were turned on at the same time, they would use a total of 3,677 W (3.677 kw) of power. 12/14

13 Appliance Power Ratings Appliance Power Rating Night light 7 W Computer 200 W Stereo 150 W Ceiling light 120 W Hair dryer 1,500 W Refrigerator 1,000 W Table lamp 60 W Television 200 W Vacuum cleaner 400 W Shop light 40 W Total 3,677 W You and the Electric Company As an electrician, you ll work very closely with the electric company, so it s a good idea to develop a positive working relationship with them. The electric company will deliver the voltage and power required to allow electrical installations to draw the amount of current they need. Electricians are responsible for installing, maintaining, and repairing every single item in an electrical system. If the installation is a house, this includes all the circuits, the circuit materials, and the service entrance. The only parts of the installation that an electrician doesn t control are the kwh meter itself and the wires that come into the house from the utility pole or transformer. The electric company provides the kwh meter. An electrician will, however, have to install the meter socket for the electric company to attach the meter to. 13/14

14 In order for you to be able to hook up to the electric company s system, your electric installation must be safe. For new installations or for major overhauls, the company may send an inspector to advise you and to ensure that your work is completely professional. In addition, your work may also have to be approved by the local city or county electrical inspector before the power company will hook up to it. Electric companies have developed layouts and procedures that will help you to do a good job. Their advice is valuable and should be heeded by everyone concerned. 14/14

### Electron Theory of Charge. Electricity. 1. Matter is made of atoms. Refers to the generation of or the possession of electric charge.

Electricity Refers to the generation of or the possession of electric charge. There are two kinds of electricity: 1. Static Electricity the electric charges are "still" or static 2. Current Electricity

### Name: Class: Date: 1. Friction can result in the transfer of protons from one object to another as the objects rub against each other.

Class: Date: Physics Test Review Modified True/False Indicate whether the statement is true or false. If false, change the identified word or phrase to make the statement true. 1. Friction can result in

### 670 Intro Physics Notes: Electric Current and Circuits

Name: Electric Current Date: / / 670 Intro Physics Notes: Electric Current and Circuits 1. Previously, we learned about static electricity. Static electricity deals with charges that are at rest. 2. Now

### Electric Charges & Current. Chapter 12. Types of electric charge

Electric Charges & Current Chapter 12 Types of electric charge Protons w/ + charge stuck in the nucleus Electrons w/ - charge freely moving around the nucleus in orbits 1 Conductors Allow the easy flow

### Electricity MR. BANKS 8 TH GRADE SCIENCE

Electricity MR. BANKS 8 TH GRADE SCIENCE Electric charges Atoms and molecules can have electrical charges. These are caused by electrons and protons. Electrons are negatively charged. Protons are positively

### Electricity. Prepared by Juan Blázquez, Alissa Gildemann. Electric charge is a property of all objects. It is responsible for electrical phenomena.

Unit 11 Electricity 1. Electric charge Electric charge is a property of all objects. It is responsible for electrical phenomena. Electrical phenomena are caused by the forces of attraction and repulsion.

### SECTION 3 BASIC AUTOMATIC CONTROLS UNIT 12 BASIC ELECTRICITY AND MAGNETISM

SECTION 3 BASIC AUTOMATIC CONTROLS UNIT 12 BASIC ELECTRICITY AND MAGNETISM Unit Objectives Describe the structure of an atom. Identify atoms with a positive charge and atoms with a negative charge. Explain

### Static Electricity. Electric Field. the net accumulation of electric charges on an object

Static Electricity the net accumulation of electric charges on an object Electric Field force exerted by an e - on anything that has an electric charge opposite charges attract like charges repel Static

### Properties of Electric Charge

1 Goals 2 Properties of Electric Charge 2 Atomic Structure: Composed of three main particles: 1. Proton 2. Neutron 3. Electron Things to Remember: 3 Everything is made of atoms. Electrons can move from

### Read Chapter 7; pages:

Forces Read Chapter 7; pages: 191-221 Objectives: - Describe how electrical charges exert forces on each other; Compare the strengths of electric and gravitational forces; Distinguish between conductors

### Electron Theory. Elements of an Atom

Electron Theory Elements of an Atom All matter is composed of molecules which are made up of a combination of atoms. Atoms have a nucleus with electrons orbiting around it. The nucleus is composed of protons

### HIGH SCHOOL SCIENCE. Physical Science 7: Electricity & Magnetism

HIGH SCHOOL SCIENCE Physical Science 7: Electricity & Magnetism WILLMAR PUBLIC SCHOOL 2013-2014 EDITION CHAPTER 7 Electricity & Magnatism In this chapter you will: 1. Analyze factors that affect the strength

### ELECTRICITY UNIT REVIEW

ELECTRICITY UNIT REVIEW S1-3-04: How does the Atomic Model help to explain static electricity? 1. Which best describes static electricity? a) charges that can be collected and held in one place b) charges

### Learning Module 2: Fundamentals of Electricity. 101 Basic Series

Learning Module 2: Fundamentals of Electricity 101 Basic Series What You Will Learn We will start with an overview to introduce you to the main points about electricity, then we will step through each

### Magnets attract some metals but not others

Electricity and Magnetism Junior Science Magnets attract some metals but not others Some objects attract iron and steel. They are called magnets. Magnetic materials have the ability to attract some materials

### ELECTRICITY Electric Fence Experiment.

ELECTRICITY Electric Fence Experiment. Can you guess what will happen? What would life be like without electricity? List 4 things that you would miss the most: 1) 2) 3) 4) Positive and Negative Charge

### An Introduction to Electricity and Circuits

An Introduction to Electricity and Circuits Materials prepared by Daniel Duke 4 th Sept 2013. This document may be copied and edited freely with attribution. This course has been designed to introduce

### Electric charges. Basics of Electricity

Electric charges Basics of Electricity Electron has a negative charge Neutron has a no charge Proton has a positive charge But what is a charge? Electric charge, like mass, is a fundamental property of

### PSC1341 Chapter 5 Electricity and Magnetism

PSC1341 Chapter 5 Electricity and Magnetism Chapter 5: Electricity and Magnetism A. The Atom B. Electricity C. Static Electricity D. A circuit E. Current and Voltage F. Resistance G. Ohm s Law H. Power

### Basic Electricity. Chapter 2. Al Penney VO1NO

Basic Electricity Chapter 2 The Structure of Matter All matter is composed of Atoms. Atoms consist of: Neutrons; Protons; and Electrons Over 100 different atoms. These are called Elements. Atoms Electrostatic

### Section 1: Electric Charge and Force

Electricity Section 1 Section 1: Electric Charge and Force Preview Key Ideas Bellringer Electric Charge Transfer of Electric Charge Induced Charges Charging by Contact Electric Force Electric Field Lines

https://www.youtube.com/watch?v=yc2-363miqs SCIENCE 9 UNIT 3 ELECTRICITY Remember: In the last unit we learned that all matter is made up of atoms atoms have subatomic particles called, protons, neutrons

### LESSON 5: ELECTRICITY II

LESSON 5: ELECTRICITY II The first two points are a review of the previous lesson 1.1.ELECTRIC CHARGE - Electric charge is a property of all objects and is responsible for electrical phenomena. -All matter

### Section 1 Electric Charge and Force

CHAPTER OUTLINE Section 1 Electric Charge and Force Key Idea questions > What are the different kinds of electric charge? > How do materials become charged when rubbed together? > What force is responsible

### Chapter 02. Voltage and Current. Atomic Theory Review. Atomic Theory Review. Atomic Theory Review. Electrical Charge.

Chapter 02 Voltage and Current Atom Atomic Theory Review Contains a nucleus of protons and neutrons Nucleus is surrounded by a group of orbiting electrons Electrons are negative, protons are positive Electrically

### Electric Force and Charge. Electric Force and Charge. Electric Force and Charge. Electric Force and Charge. Electric Force and Charge

Hewitt/Lyons/Suchocki/Yeh Conceptual Integrated Science Chapter 7 ELECTRICITY AND MAGNETISM Electric forces can attract some objects and repel others Electric charge: the fundamental quantity that underlies

### Basic Electricity Video Exam

Name: Class: Date: Basic Electricity Video Exam Multiple Choice Identify the choice that best completes the statement or answers the question. 1. Matter is made of. a. plasma, gas, and solid b. solid,

### Electricity is the movement of electrical charge through a circuit (usually, flowing electrons.) The Greek word for amber is electron

Electricity is the movement of electrical charge through a circuit (usually, flowing electrons.) The Greek word for amber is electron Women in ancient Greece noticed that rubbing their amber jewelry against

### CHARGE AND ELECTRIC CURRENT:

ELECTRICITY: CHARGE AND ELECTRIC CURRENT ELECTRIC CHARGE ELECTRIC CURRENT ELECTRIC CIRCUIT DEFINITION AND COMPONENTS EFFECTS OF ELECTRIC CURRENT TYPES OF CIRCUITS ELECTRIC QUANTITIES VOLTAGE CURRENT RESISTANCE

### 9. Which of the following is the correct relationship among power, current, and voltage?. a. P = I/V c. P = I x V b. V = P x I d.

Name: Electricity and Magnetism Test Multiple Choice Identify the choice that best completes the statement. 1. Resistance is measured in a unit called the. a. ohm c. ampere b. coulomb d. volt 2. The statement

### Introduction. Upon completion of Basics of Electricity you will be able to: Explain the difference between conductors and insulators

Table of Contents Introduction...2 Electron Theory...4 Conductors, Insulators and Semiconductors...5 Electric Charges...7 Current...9 Voltage...11 Resistance...13 Simple Electric Circuit...15 Ohm s Law...16

### MITES Middle School Introduction To Engineering Systems

MITES Middle School Introduction To Engineering Systems 2 Expectations for Behavior Be Respectful To teacher, To Peers, To Facilities Follow 1 st Request From Teachers or Peers Golden Rule Treat others

### STUDY GUIDE CHAPTER 5 ELECTRICITY AND MAGNETISM 1) ASSOCIATE ELEMENTARY PARTICLES WITH THEIR ELECTRICAL CHARGE

Name Date STUDY GUIDE CHAPTER 5 ELECTRICITY AND MAGNETISM 1) ASSOCIATE ELEMENTARY PARTICLES WITH THEIR ELECTRICAL CHARGE Scientists now know that an atom is composed of even smaller particles of matter:

### Electricity and Electromagnetism SOL review Scan for a brief video. A. Law of electric charges.

A. Law of electric charges. Electricity and Electromagnetism SOL review Scan for a brief video The law of electric charges states that like charges repel and opposite charges attract. Because protons and

### Chapter 8. Electricity and Magnetism. Law of Charges. Negative/Positive

Chapter 8 Electricity and Magnetism Electricity and Magnetism (1) Electric Charge Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic

### Preliminary Course Physics Module 8.3 Electrical Energy in the Home Summative Test. Student Name:

Summative Test Student Name: Date: / / IMPORTANT FORMULAE I = Q/t V = I.R R S = R 1 + R 2 +.. 1/R P = 1/R 1 + 1/R 2 + P = V.I = I 2.R = V 2 /R Energy = V.I.t E = F/q Part A. Multiple Choice Questions 1-20.

### Electricity. Year 10 Science

Electricity Year 10 Science What is electricity? The collection or flow of electrons in the form of an electric charge What is static electricity? A stationary electrical charge that is built up on the

### Electricity. dronstudy.com

Electricity Electricity is a basic part of our nature and it is one of our most widely used forms of energy. We use electricity virtually every minute of every day for example in lighting, heating, refrigeration,

### Electromagnetism Review Sheet

Electromagnetism Review Sheet Electricity Atomic basics: Particle name Charge location protons electrons neutrons + in the nucleus - outside of the nucleus neutral in the nucleus What would happen if two

### Closed loop of moving charges (electrons move - flow of negative charges; positive ions move - flow of positive charges. Nucleus not moving)

Unit 2: Electricity and Magnetism Lesson 3: Simple Circuits Electric circuits transfer energy. Electrical energy is converted into light, heat, sound, mechanical work, etc. The byproduct of any circuit

### Joy of Science Discovering the matters and the laws of the universe

Joy of Science Discovering the matters and the laws of the universe Key Words Universe, Energy, Quantum mechanics, Chemical reaction, Structure of matter Unless otherwise noted, copied pictures are taken

### Electroscope Used to are transferred to the and Foil becomes and

Electricity Notes Chapter 17 Section 1: Electric Charge and Forces Electric charge is a variety of independent all with one single name. Electricity is related to, and both (-) and (+) carry a charge.

### Electricity Review completed.notebook. June 13, 2013

Which particle in an atom has no electric charge associated with it? a. proton c. neutron b. electron d. nucleus Jun 12 9:28 PM The electrons in a metal sphere can be made to move by touching it with a

CHAPTER 12 ELECTRICITY Electricity is a general term that encompasses a variety of phenomena resulting from the presence and flow of electric charge. These include many easily recognizable phenomena such

### SYSTEMS OF UNITS. 1 st Class Basic of Electrical Engineering. Current and Voltage

SYSTEMS OF UNITS In the past, the systems of units most commonly used were the English and metric, as outlined in Table below. Note that while the English system is based on a single standard, the metric

### ELECTRICITY. Chapter ELECTRIC CHARGE & FORCE

ELECTRICITY Chapter 17 17.1 ELECTRIC CHARGE & FORCE Essential Questions: What are the different kinds of electric charge? How do materials become charged when rubbed together? What force is responsible

### Introduction to Electricity

Introduction to Electricity Principles of Engineering 2012 Project Lead The Way, Inc. Electricity Movement of electrons Invisible force that provides light, heat, sound, motion... Electricity at the Atomic

### Electricity. Chapter 21

Electricity Chapter 21 Electricity Charge of proton Positive Charge of electron Negative Charge of neutron NONE Atoms have no charge because the charges of the protons and electrons cancel each other out.

### What is electricity? Charges that could be either positive or negative and that they could be transferred from one object to another.

Electricity What is electricity? Charges that could be either positive or negative and that they could be transferred from one object to another. What is electrical charge Protons carry positive charges

### Differentiate between AC and DC. Identify the most common source of DC voltage. Describe how to connect DC voltage sources so that voltages will add.

Objectives Explain the similarities and differences between Newton s law of universal gravitation and Coulomb s law. Explain how the force between two like charges and the force between two unlike charges

### 1 of 23. Boardworks Ltd Electrical Power

1 of 23 Boardworks Ltd 2016 Electrical Power Electrical Power 2 of 23 Boardworks Ltd 2016 What is electrical power? 3 of 23 Boardworks Ltd 2016 Electrical power is the rate at which energy is transferred

### Basics of Electricity

Siemens STEP 2000 Course Basics of Electricity It's easy to get in STEP! Download any course. Hint: Make sure you download all parts for each course and the test answer form. Complete each chapter and

### Notes: Ohm s Law and Electric Power

Name: Date: / / 644 Intro Physics Notes: Ohm s Law and Electric Power Ohm s Law: Important Terms Term Symbol Units Definition 1. current I amps flow of electric charges through a conductor 2. voltage V

### Chapter 7. Electricity. Teacher Answer Key. Broughton High School of Wake County

Teacher Answer Key Broughton High School of Wake County 1 Chapter 7 Electricity Physical Science Vocabulary 2 Vocabulary for Chapter 7 Electricity Vocabulary Word Definition 1. Charging by Contact 2. Charging

### ELECTRON THEORY

ELECTRON THEORY We will start our discussion of electron theory with a few definitions. Matter- is anything that has mass and takes up space. The basic unit of matter is the atom. Another Definition Energy-

### Material World Electricity and Magnetism

Material World Electricity and Magnetism Electrical Charge An atom is composed of small particles of matter: protons, neutrons and electrons. The table below describes the charge and distribution of these

### Conceptual Physical Science 6 th Edition

Conceptual Physical Science 6 th Edition Chapter 8: STATIC AND CURRENT ELECTRICITY 1 Chapter 8: STATIC AND CURRENT ELECTRICITY Chapter 8: Read: All Homework: Four problems from the following set: 4, 6,

### MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Practice Exam 4 Sci1600 S18 Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Two particles with the electric charges Q1 and Q2 repel each other.

### MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Practice Exam 4 Sci1600 S18 KEY Name MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Two particles with the electric charges Q1 and Q2 repel each

### Gas discharges. Current flow of electric charge. Electric current (symbol I) L 26 Electricity and Magnetism [3] examples of electrical discharges

L 26 Electricity and Magnetism [3] Electric circuits what conducts electricity what doesn t t conduct electricity Current voltage and resistance Ohm s s Law Heat in a resistor power loss Making simple

### WHAT ARE THE EFFECTS OF MOVING CHARGES?

ELECTRICITY WHAT ARE THE EFFECTS OF MOVING CHARGES? ELECTRICAL CHARGES Most atoms have the same number of protons and electrons. They often lose and gain electrons. When this happens, the atom s charge

### Ohm s Law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit.

Quantity What is Ohm s Law? Ohm s Law is a formula used to calculate the relationship between voltage, current and resistance in an electrical circuit. To students of electronics, Ohm s Law (E = IR) is

### - Memorize the terms voltage, current, resistance, and power. - Know the equations Ohm s Law and the Electric Power formula

E: Know Circuit Vocabulary (Short Answer) Level 2 Prerequisites: Know Circuit Vocabulary (Short Answer); Recognize Insulators and Conductors Objectives: - Memorize the terms voltage, current, resistance,

### f Static Electricity:

ELECTRICITV VOCflB WORDS Electricity: f Static Electricity: Current Electricity: Electron: Neutron: Proton: Attraction: Repulsion: / ^ Source: Conductor: Insulator: Load: Switch: Series Circuit: Parallel

### National 5 Physics. Language Wikipedia. Electricity

National 5 Physics Catlin.Fatu@English Language Wikipedia Electricity Throughout the Course, appropriate attention should be given to units, prefixes and scientific notation. tera T 10 12 x 1,000,000,000,000

### Circuit Analysis I (ENGR 2405) Chapter 1 Review: Charge, Current, Voltage, Power

Circuit Analysis I (ENGR 2405) Chapter 1 Review: Charge, Current, Voltage, Power What is a circuit? An electric circuit is an interconnection of electrical elements. It may consist of only two elements

### 3. The figure above shows two pith balls suspended by threads from a support. In the figure,

3. The figure above shows two pith balls suspended by threads from a support. In the figure, Student ID: 22133336 Exam: 002901RR - Electronics Basics When you have completed your exam and reviewed your

### Dynamic Electricity. All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison

Dynamic Electricity All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison Review Everything is made of atoms which contain POSITIVE particles called PROTONS and NEGATIVE

### Electric Currents and Circuits

Electric Currents and Circuits Producing Electric Current Electric Current flow of charged particles Need a potential difference to occur Conventional Current- flow of positive charges flowing from positive

### Note on Posted Slides. Flow of Charge. Electricity/Water Analogy: Continuing the Analogy. Electric Current

Note on Posted Slides These are the slides that I intended to show in class on Tue. Mar. 18, 2014. They contain important ideas and questions from your reading. Due to time constraints, I was probably

### Section 3. Series and Parallel Circuits: Lighten Up. What Do You See? What Do You Think? Investigate

Section 3 Series and Parallel Circuits: Lighten Up Florida Next Generation Sunshine State Standards: Additional Benchmarks met in Section 3 What Do You See? SC.912.N.2.4 Explain that scientific knowledge

### NATIONAL 5 PHYSICS ELECTRICITY

NATIONAL 5 PHYSICS ELECTRICITY ELECTRICAL CHARGE CARRIERS AND CURRENT Electrical Charge Electrical charge exists in two distinct types positive charge and negative charge. It is also possible for an object

### Chapter 33 - Electric Fields and Potential. Chapter 34 - Electric Current

Chapter 33 - Electric Fields and Potential Chapter 34 - Electric Current Electric Force acts through a field An electric field surrounds every electric charge. It exerts a force that causes electric charges

### What are the two types of current? The two types of current are direct current and alternating current.

Electric Current What are the two types of current? The two types of current are direct current and alternating current. Electric Current The continuous flow of electric charge is an electric current.

### Lesson Plan: Electric Circuits (~130 minutes) Concepts

Lesson Plan: Electric Circuits (~130 minutes) Concepts 1. Electricity is the flow of electric charge (electrons). 2. Electric Charge is a property of subatomic particles. 3. Current is the movement of

### Introduction to Electrical Theory

Youth xplore Trades Skills Introduction to lectrical Theory Description Working as an electrician requires many skills. The physical demands of the job are one important part of the skills needed to succeed.

### Yr. 9 Electricity WorkBook

Yr. 9 Electricity WorkBook On completion of this booklet students should be able to: Recall the structure of a neutral atom: three particles, their charges, their location; Nucleus (Proton positive, Neutron-

### Electrical Theory Lesson 1: Electricity and Electronics

Page 1: Welcome to Lesson 1 of Electrical Theory. This lesson covers the following objectives: Identify the relationship between elements and compounds. Construct a model of an atom. Discuss the concepts

### Name Period. Electricity. Session 1- Static Electricity

Session 1- Static Obj: Explore electricity and subatomic particles, focusing on static electricity Need: Static worksheet, Plasma Panel 1. Using the science dictionary: Sub- is a prefix that means or 2.

### Electricity Courseware Instructions

Physics Electricity Courseware Instructions This courseware acts as a supplement to the classroom instruction. The five sections on the following slide link to the topic areas. Following the topic area

### V R I = UNIT V: Electricity and Magnetism Chapters Chapter 34: Electric Current. volt ohm. voltage. current = I. The Flow of Charge (34.

IMPORTANT TERMS: Alternating current (AC) Ampere Diode Direct current (DC) Electric current Electric power Electric resistance Ohm Ohm s Law Potential difference Voltage source EQUATIONS: UNIT V: Electricity

### Theme 5: Electricity in the Home

Theme 5: Electricity in the Home Static Electricity WHAT IS STATIC ELECTRICITY? Everything we see is made up of tiny little parts called atoms. So what are atoms made of? In the middle of each atom is

### Some differences: Some basic similarities: Charges. Electrons vs. Protons 4/3/15. Chapters 22-25: Electromagnetism!

Chapters 22-25: Electromagnetism! Electric Force vs. Gravitational Force What properties does the gravitational force depend on? What properties does the electric force depend on? F grav = Gm 1 m 2 /d

### 8. Electric circuit: The closed path along which electric current flows is called an electric circuit.

GIST OF THE LESSON 1. Positive and negative charges: The charge acquired by a glass rod when rubbed with silk is called positive charge and the charge acquired by an ebonite rod when rubbed with wool is

### Electric Charge and Force

CHAPTER 17 21 SECTION Electricity Electric Charge and Force KEY IDEAS As you read this section, keep these questions in mind: What are the different kinds of electric charge? How do materials become electrically

### Circuit Analysis and Ohm s Law

Study Unit Circuit Analysis and Ohm s Law By Robert Cecci Circuit analysis is one of the fundamental jobs of an electrician or electronics technician With the knowledge of how voltage, current, and resistance

### Test Review Electricity

Name: Date: 1. An operating television set draws 0.71 ampere of current when connected to a 120-volt outlet. Calculate the time it takes the television to consume 3.0 10 5 joules of electric energy. [Show

### Chapter19-Magnetism and Electricity

Chapter19-Magnetism and Electricity Magnetism: attraction of a magnet for another object. Magnetic poles: north & south ends of a magnet, they exert the strongest forces Like poles repel each other, unlike

### Part 4: Electricity & Magnetism

Part 4: Electricity & Magnetism Notes: Magnetism Magnetism Magnets: 1.Have a north and south pole 2.Like poles repel; opposite poles attract - The larger the distance between the magnets, the weaker the

### Upon completion and review of this chapter, you should be able to:

Chapter 2 Basic Theories Upon completion and review of this chapter, you should be able to: Explain the theories and laws of electricity. Describe the difference between insulators, conductors, and semiconductors.

### Chapter 19, Electricity Physical Science, McDougal-Littell, 2008

SECTION 1 (PP. 633-641): MATERIALS CAN BECOME ELECTRICALLY CHARGED. Georgia Standards: S8P2c Compare and contrast the different forms of energy (heat, light, electricity, mechanical motion, sound) and

### Essential Questions: How does electricity work, and why does it form? How can electricity be useful?

Essential Questions: How does electricity work, and why does it form? How can electricity be useful? Appliances Lamps Computers Refrigerators Microwaves Flashlights Cell phones Video games All matter is

### TRADE OF HEAVY VEHICLE MECHANIC

TRADE OF HEAVY VEHICLE MECHANIC PHASE 2 Module 2 /Batteries UNIT: 2 Table of Contents 1. Learning Outcome... 1 1.1 Key Learning Points... 1 2.0 Electricity... 2 2.1 Composition of Substances... 3 2.2 Free

### Chapter.16 / Section.1: Electric Charge. Q=Ne Total Charge=number of electrons transferred fundamental charge

Revision Sheet for the Final Exam Academic Year: 2018/2019 First Term Subject: Physics Grade: 12 Student s name:. Date: 26/11/2017 Required Material: Chapter 16: Electric Forces and Fields, Sections: (1,

### Direct Currents. We will now start to consider charges that are moving through a circuit, currents. Sunday, February 16, 2014

Direct Currents We will now start to consider charges that are moving through a circuit, currents. 1 Direct Current Current usually consists of mobile electrons traveling in conducting materials Direct

### Electricity CHAPTER ELECTRIC CURRENT AND CIRCUIT

CHAPTER 12 Electricity Electricity has an important place in modern society. It is a controllable and convenient form of energy for a variety of uses in homes, schools, hospitals, industries and so on.

### A Review of Circuitry

1 A Review of Circuitry There is an attractive force between a positive and a negative charge. In order to separate these charges, a force at least equal to the attractive force must be applied to one

### Ohm's Law and Resistance

Ohm's Law and Resistance Resistance Resistance is the property of a component which restricts the flow of electric current. Energy is used up as the voltage across the component drives the current through