Electric Current. Volta

Size: px
Start display at page:

Download "Electric Current. Volta"

Transcription

1 Electric Current Galvani Volta In the late 1700's Luigi Galvani and Alessandro Volta carried out experiements dealing with the contraction of frogs' leg muscles. Volta's work led to the invention of the electric battery (voltaic cell) which produced the first steady flow of charged particles. In honor of his work in the field of electricity, the electrical unit known as the volt, V, was named in his honor.

2 Electric Current The rate of flow of electric charge is called electric current. Electric current in a wire can be defined as the amount of charge that passes through it per unit time at any point. I is electric current q is quantitiy of charge t is time interval Electric current is measured in coulombs per second. One coulomb per second is called an ampere (amp). Current is often measured in ma (milliamps) and μa (microamps). 1 ma = 1 x 10 3 A 1μA = 1 x 10-6 A

3 Conventional Current vs. Electron Flow Conventional Current vs. Electron Flow

4 Sample Problems 1. A steady current of 3.5 A flowed in a wire for 2.0 minutes. How much charge passed through the circuit?

5 2. A battery was charged using a current of 5.7 A. How long did it take to charge the battery if 1.2 x 10 5 C of charge passed through it?

6 3. What is the current if 2000 Na + ions were to flow across a cell membrane in 9.8 μs? The charge on a sodium ion is the same as a proton.

7 Electric Circuits An electric circuit is a closed loop or continuous path that consists of a device that will increase the potential energy of electric charges, such as batteries generators photovoltaic cells (devices that change sunlight directly into electricity) connected to a device (radio, lamp, toaster) that reduces the potential energy of the charges while converting the electrical energy into a form of "useful" energy (sound, light, heat). In order to keep the charge flowing, a potential difference must be maintained.

8 Electric Potential in Circuits A battery powered electric circuit has locations of high and low potential. Within the battery, there is an electric field established between the two terminals, directed from the positive towards the negative terminal. D Work is required to move a positive charge through the battery from the negative terminal to the positive terminal, thus increasing the potential energy of the charge. (The charge is moving against the electric field.) D q It is for this reason that the positive terminal is described as the high potential terminal. high potential D q The movement of the positive charge through the wires from the positive terminal to the negative terminal would occur naturally. (No work is required to move the charge in the direction of the electric field.) The charge loses potential energy as it moves through the wires. It is for this reason that the negative terminal is described as the low potential terminal. high potential D low potential q This assignment of high and low potential to the terminals of the battery presumes that we are using conventional current.

9 An electric circuit is nothing more than an energy conversion system. The reaction of the chemicals inside a battery produces chemical energy that is used to do work on positive charge to move it from the low potential terminal to the high potential terminal. Chemical energy is transformed into electric potential energy within the internal circuit (the battery). Once at the high potential terminal, the positive charge will then move through the external circuit and do work on a light bulb, a motor, heater coils, etc., transforming its electric potential energy into useful forms for which the circuit was designed.

10 A Simple Circuit Below is a simple electric circuit. It has a switch, a bulb and a battery. These components are connected together with metal connecting wires. A simple switch is made of a metal lever that can join up with a metal contact. When you press the switch, the two pieces of metal touch and the current can flow through it. When you open it, this breaks the circuit. Charge flows all the way around the circuit. The battery pushes the charge around the circuit. As the charge passes through the lamp, it makes it light up.

11 Resistance and Ohm's Law The relationhsip between the current, I, in a metal wire and the potential difference, V, applied to its ends, was experimentally determined by Georg Ohm. Ohm He found that current is directly proportional to potential difference. I α V This means that if you connect a wire to a 9 V battery, the current will be three times what it would be if the wire were connected to a 3 V battery. The amount of current that flows in a circuit is also dependent on the resistance offered by the circuit. Example Imagine you are walking down the hall during first period. You might meet a few people along the way, but you won't encounter much opposition. Compare that situation to walking down the hall a few seconds after the lunch bell rings you will encounter a lot of resistance! Current, I is inversely proportional to resistance, R. I α 1 R

12 If we combine the two relationships, we get: I = V R I is current V is potential difference R is resistance The unit of resistance is the ohm. The symbol for ohm is the Greek letter omega, Ω. 1 Ω = 1 V A The equation is usually written as V = IR and it is referred to as "Ohm's Law." Not all materials obey the law, but we will assume the materials invovled in our problems do.

13 Resistors Connecting wires generally have very low resistance compared to the coils or filaments in some electrical devices like heaters and light bulbs. Resistors are devices designed to have a specific resistance and are often used in electronic devices to control the amount of current that flows. Some resistors have their resistance values written on their exteriors. Others have a color code that allows us to calculate their resistance.

14 Four band identification is the most commonly used for color coding resistors. It consists of four colored bands that are painted aorund the body of the resistor. The first two numbers are the first two significant digits of the resitance value, the third is a mulitplier and the fourth is the tolerance of the value. Each color corresponds to a certain number, shown in the chart below. The tolerance for a 4 band resistor will be 2%, 5% or 10%. A useful mnemonic for remembering the first ten color codes matches the first letter of the color code, by order of increasing magnitude. There are many variations: Bright Boys Rave Over Young Girls But Veto Getting Wed B. B. R O Y of Great Britain has a Very Good Wife Better Be Right Or Your Great Big Venture Goes West

15

16 Sample Problems 1. What is the resistance of a toaster if 1.10 x 10 2 V produces a current of 3.1 A?

17 2. A 4.5 V battery is connected to a bulb whose resistance is 2.5 Ω. What is the current?

18 3. A hair dryer draws 11.0 A when plugged into a 1.20 x 10 2 V line. How much charge passes through in 10.0 minutes?

19 Experimentally it has been found that the resistance, R, of a metal is directly proportional to its length, L, and inversely proportional to its cross sectional area, A. R = ρl A R resistance ρ resistivity L length A cross sectional area ρ is the Greek letter rho and it is a proportionality constant called resistivity that depends on the material from which the wire is made. The resistivities of some metals are listed below. Material Resistivity (Ωm) silver 1.59 x 10 8 copper 1.68 x 10 8 aluminum 2.65 x 10 8 tungsten 5.6 x 10 8 iron 9.71 x 10 8 platinum 10.6 x 10 8

20 To find the cross sectional area of the the wire, use the following formula: where d represents the diameter of the wire

21 Sample Problems 1. What is the resistance of a 3.5 m length of aluminum wire 1.5 mm in diameter?

22 2. What is the length of a copper wire that has a crosssectional area of 3.4 x 10 6 m 2 and a resistance of 7.1 x 10 2 Ω?

23 3. What is the radius of a 1.00 m length of tungsten wire whose resistance is 0.25 Ω?

24 Electric Power Electric power measures the rate at which electric energy is transformed into another form of energy such as light or heat. The energy transformed when a charge, Q, moves through a potential difference, V, is QV. Power can be calculated as follows: P = QV t Remember that I = Q/t, so the formula becomes: P = IV P power I electric current V potential difference The unit of electric power is the watt, W. 1W = 1 J s

25 By substituting V/R for I, or IR for V, we can get two more equations for electric power. P = IV P = V (V) R P = V 2 R P = IV P = I (IR) P = I 2 R

26 Sample Problems 1. Calculate the resistance of a 60.0 W bulb designed for 12 V?

27 2. What is the maximum power consumption of a 6.0 V tape player that draws a maximum of 4.50 x 10 2 ma of current?

28 3. An 8.00 x 10 2 W hair dryer has a resistance of 18 Ω. What is the current throught the hair dryer?

29 If you look at an electric bill, you will see that you pay for energy not power. We can calculate the electric energy used by a device by multiplying power consumption by the time the device is on. E = Pt E energy P power t time We could write the units of energy as Ws. The electric company uses a larger unit, the kilowatt hour (kwh). 1 kwh = 1000 W x 3600 s = 3.60 x 10 6 J Another equation that is often used to calculate electric energy is: E = I 2 Rt

30 Sample Problem 1. An electric heater draws 15.0 A on a 1.20 x 10 2 V line. How much does it cost to operate the heater for 30.0 days if the heater is used for 3.00 h per day and the electric company charges 10.5 cents per kwh? Determine the total number of hours the heater is used. t = 3.00 hours per day x 30.0 days = 90.0 hours Determine the amount of power that is used. P = IV P = 15.0 x 1.20 x 10 2 P = 1.80 x 10 3 W P = 1.80 kw Calculate the amount of energy that was used. E = Pt E = 1.80 kw x 90.0 h E = 1.62 x 10 2 kwh Now calculate cost. Cost = (1.62 x 10 2 kwh)($0.105) kwh Cost = $17.00

31 2. A small electric furnace operating on 1.00 x 10 2 V, expends 2.0 kw of power. a) What current is in the circuit? b) What is the resistance of the furnace? c) What is the cost of operation for 24 h at $0.05/kWh?

32 Diagramming Circuits There are standard symbols that are used to represent the elements of a circuit. The diagram that you end up with is called a circuit schematic or circuit diagram. We will be using the following symbols: connector (wire) ammeter battery + voltmeter (or ) resistor Arrows are used to show the direction of the current. Reminder Although electricity is the flow of electrons, called electron flow, it was originally thought that positive charge flowedin a circuit. The flow of positive charge is called conventional urrent.

33 In a circuit, resistors can either be arranged in series with one another or parallel to another. Resistors in Series All the resistors are connected one after the other. There is only one path for the charge to follow. R 1 V + R 2 R 3 Since it is one continuous loop, the current throughout the loop is the same. The total current is equal to the current in resistor 1, resistor 2 and resistor 3. I T = I 1 = I 2 = I 3

34 The increase in potential across the battery, is equal to the sum of the potential drops at each resistor. V T = V 1 +V 2 + V 3 To find the total resistance of a series circuit, sum the resistances in each resistor. R T = R 1 + R 2 + R 3 Total resistance is also referred to as the effective or equivalent resistance.

35 Sample Problem A 45.0 V potential difference is place across a 5.0 Ω resistor and a 10.0 Ω resistor connected in series. a) What is the eqivalent resistance of the circuit? b) What is the current through the circuit? c) What is the voltage drop across each resistor? d) What is the total voltage drop across the circuit? We can use a V I R chart to keep track of our values. Fill in the known values a) equivalent resistance = total resistance R T = R 1 + R 2 (add the values in the third column!) Fill this value into the chart

36 b) current through the circuit = total current We now have two values in the "Total" row. Using Ohm's law, we can determine the third, the total current. I T = V T /R T Reminder I T = I 1 = I 2 Fill the values of I T, I 1 and I 2 into the chart

37 c) voltage drop across each resistor We now have two values in the "R 1 " row and the "R 2 " row. Using Ohm's law, we can determine the third value, V, for each resistor. Fill these values into the chart

38 d) total voltage drop across the resistor This value was given! Verify to make sure that: V T = V 1 +V 2

39 Resistors in Parallel Parallel circuits are made by connecting resistors in such a way that you create several paths/branches through which current can flow. For the resistors to be truly in parallel, the current must split, then come back together. In the example given below, the current has three possible paths it can take. current splits here V + Path 1 Path 2 Path 3 R 1 R 2 R 3 current comes together here

40 The total current in the circuit is equal to the sum of the currents in each path. I T = I 1 + I 2 + I 3 The battery provides the source of potential difference for the circuit. Each path acts as if the other paths are not present. All the potential drops are the same. V T = V 1 = V 2 = V 3

41 The equivalent resistance of a parallel circuit can be found using the following formula, Placing a resistor in parallel with an existing resistor always decreases the resistance of the circuit. The resistance decreases because each new resistor provides an additional path for the current to flow. NOTE The equivalent resistance is always less that the resistance of any resistor in the circuit.

42 Derivation of the formula for the equivalent resistance of a parallel circuit. The total current in the circuit is the sum of the currents through the branches of the circuit. I = I 1 + I 2 + I 3 The total current through the equivalent resistance, R, is given by I = V/R, but all the potential drops in the circuit are the same. V = V + V + V R R 1 R 2 R 3 Dividing both sides of the equation by V gives an equation for the equivalent resistance of the paralle resistors.

43 Sample Problem Three resistors of 60.0 Ω, 30.0 Ω and 20.0 Ω are connected in parallel across a 90.0 V difference in potential. a) Find the equivalent resistance of the circuit. b) Find the current in the entire circuit. c) FInd the current through each branch of the circuit. We will use a V I R chart to keep track of our values. Fill in the known values. a) equivalent resistance Fill this value into the chart Note that the equivalent resistance is less than resistance of any resistor in the circuit.

44 10.0 b) current in the entire circuit We now have two values in the "Total" row. Using Ohm's law, we can determine the third, the total current. I T = V T /R T Fill this value into the chart

45 c) voltage drop across each resistor We now have two values in the "R 1 " row, the "R 2 " row and the "R 3 " row. Using Ohm's law, we can determine the third value, V, for each resistor. Fill these values into the chart Verify to make sure that: I T = I 1 + I 2 + I 3

46 Combination Circuits Find the total resistance and current, then find the individual voltages and currents for each of the resistors in this circuit: R 1 5 Ω R 2 7 Ω 12 V + R 3 10 Ω Fill in the known values. Fill in the known values.

47 R 1 5 Ω R 2 7 Ω 12 V + R 3 10 Ω Next, simplify the circuit. Calculate the equivalent resistance for the parallel part of the circuit. We will call this resistance, R A. R 1 5 Ω R A 12 V +

48 R 1 5 Ω R A 12 V + Now, calculate the equivalent resistance of the entire circuit, R T. Do this by following the rule for resistors in series. Fill this value into the chart.

49 We now have two values in the "Total" row. Using Ohm's law, we can determine the third, the total current, I T. I T = V T / R T Fill this value into the chart.

50 All the current that flows through the circuit will also flow through R 1 because it is in series with the battery. We now have two of the three values in the R 1 row. We can find V 1 using Ohm's law. V 1 = I 1 R 1 Fill this value into the chart.

51 If V T is 12 V and the drop in potential at R 1 is 6.5 V, then there is still to be used up. 12 V 6.5 V = 5.5 V We know that the voltage drops at R 2 and R 3 are equal because they are connected in parallel. Therefore, V 2 = 5.5 V and V 3 = 5.5 V Fill these values into the chart.

52 Determine I 2 and I 3 using Ohm's Law. Complete the chart. Note that the sum of I 2 and I 3 is ~1.3 A.

53 R 1 2 Ω 9 V + R 2 5 Ω R 4 3 Ω R 3 1 Ω

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

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

More information

Chapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc.

Chapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc. Chapter 25 Electric Currents and Resistance 25-4 Resistivity Example 25-5: Speaker wires. Suppose you want to connect your stereo to remote speakers. (a) If each wire must be 20 m long, what diameter copper

More information

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

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.

More information

Continuous flow of electric charges. Current Electricity

Continuous flow of electric charges. Current Electricity Continuous flow of electric charges Current Electricity Did You Know? The voltage across a muscle cell in your body is about 70 millivolts. A millivolt (mv) is one thousandth of a volt. AC and DC DC Direct

More information

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

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

More information

ELECTRICITY. Prepared by: M. S. KumarSwamy, TGT(Maths) Page

ELECTRICITY. Prepared by: M. S. KumarSwamy, TGT(Maths) Page ELECTRICITY 1. Name a device that helps to maintain a potential difference across a conductor. Cell or battery 2. Define 1 volt. Express it in terms of SI unit of work and charge calculate the amount of

More information

Chapter 19. Electric Current, Resistance, and DC Circuit Analysis

Chapter 19. Electric Current, Resistance, and DC Circuit Analysis Chapter 19 Electric Current, Resistance, and DC Circuit Analysis I = dq/dt Current is charge per time SI Units: Coulombs/Second = Amps Direction of Electron Flow _ + Direction of Conventional Current:

More information

Lecture (07) Electric Current and Resistance By: Dr. Ahmed ElShafee Dr. Ahmed ElShafee, ACU : Spring 2015, Physics II

Lecture (07) Electric Current and Resistance By: Dr. Ahmed ElShafee Dr. Ahmed ElShafee, ACU : Spring 2015, Physics II Lecture (07) Electric Current and Resistance By: Dr. Ahmed ElShafee ١ The glow of the thin wire filament of a light bulb is caused by the electric current passing through it. Electric energy is transformed

More information

ELECTRICITY UNIT REVIEW

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

More information

Unit 6 Current Electricity and Circuits

Unit 6 Current Electricity and Circuits Unit 6 Current Electricity and Circuits 2 Types of Electricity Electricity that in motion. Electricity that in motion. Occurs whenever an moves through a. 2 Types of Current Electricity Electricity that

More information

Electric Current & DC Circuits

Electric Current & DC Circuits Electric Current & DC Circuits Circuits Click on the topic to go to that section Conductors Resistivity and Resistance Circuit Diagrams Measurement EMF & Terminal Voltage Kirchhoff's Rules Capacitors*

More information

LESSON 5: ELECTRICITY II

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

More information

Downloaded from

Downloaded from 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

More information

A Review of Circuitry

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

More information

Electricity CHAPTER ELECTRIC CURRENT AND CIRCUIT

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.

More information

1 of 23. Boardworks Ltd Electrical Power

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

More information

Electricity. dronstudy.com

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,

More information

Algebra Based Physics

Algebra Based Physics Page 1 of 105 Algebra Based Physics Electric Current & DC Circuits 2015-10-06 www.njctl.org Page 2 of 105 Electric Current & DC Circuits Circuits Conductors Resistivity and Resistance Circuit Diagrams

More information

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

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

More information

Read Chapter 7; pages:

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

More information

CHARGE AND ELECTRIC CURRENT:

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

More information

RECALL?? Electricity concepts in Grade 9. Sources of electrical energy Current Voltage Resistance Power Circuits : Series and Parallel

RECALL?? Electricity concepts in Grade 9. Sources of electrical energy Current Voltage Resistance Power Circuits : Series and Parallel Unit 3C Circuits RECALL?? Electricity concepts in Grade 9. Sources of electrical energy Current Voltage Resistance Power Circuits : Series and Parallel 2 Types of Electricity Electrostatics Electricity

More information

Resistivity and Temperature Coefficients (at 20 C)

Resistivity and Temperature Coefficients (at 20 C) Homework # 4 Resistivity and Temperature Coefficients (at 0 C) Substance Resistivity, Temperature ( m) Coefficient, (C ) - Conductors Silver.59 x 0-0.006 Copper.6 x 0-0.006 Aluminum.65 x 0-0.0049 Tungsten

More information

What is a Circuit? We know that electricity is the flow of electrons. If the electrons cannot move there is now electricity.

What is a Circuit? We know that electricity is the flow of electrons. If the electrons cannot move there is now electricity. Electrical Circuits This guide covers the following: What is a circuit? Circuit Symbols Series and Parallel Circuits Electrical Charge Voltage Current Current and Voltage in Series and Parallel circuits

More information

Electric Current & DC Circuits How to Use this File Electric Current & DC Circuits Click on the topic to go to that section Circuits

Electric Current & DC Circuits  How to Use this File Electric Current & DC Circuits Click on the topic to go to that section Circuits Slide 1 / 127 Slide 2 / 127 Electric Current & DC Circuits www.njctl.org Slide 3 / 127 How to Use this File Slide 4 / 127 Electric Current & DC Circuits Each topic is composed of brief direct instruction

More information

ELECTRICITY & CIRCUITS

ELECTRICITY & CIRCUITS ELECTRICITY & CIRCUITS Reason and justice tell me there s more love for humanity in electricity and steam than in chastity and vegetarianism. Anton Chekhov LIGHTNING, PART 2 Electricity is really just

More information

10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge?

10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge? Year 11 Physics Electrical Energy in the Home Name: 1. Draw the electric field lines around a) a single positive charge b) between two opposite charged bodies c) two parallel plates + + + + + + + - - -

More information

Greek Letter Omega Ω = Ohm (Volts per Ampere)

Greek Letter Omega Ω = Ohm (Volts per Ampere) ) What is electric current? Flow of Electric Charge 2) What is the unit we use for electric current? Amperes (Coulombs per Second) 3) What is electrical resistance? Resistance to Electric Current 4) What

More information

Notes on Electricity (Circuits)

Notes on Electricity (Circuits) A circuit is defined to be a collection of energy-givers (batteries) and energy-takers (resistors, light bulbs, radios, etc.) that form a closed path (or complete path) through which electrical current

More information

(b) State the relation between work, charge and potential difference for an electric circuit.

(b) State the relation between work, charge and potential difference for an electric circuit. Question Bank on Ch-Electricity 1. (a) Define the S.I unit of potential difference. (b) State the relation between work, charge and potential difference for an electric circuit. Calculate the potential

More information

Current and Resistance

Current and Resistance Current and Resistance 1 Define the current. Understand the microscopic description of current. Discuss the rat at which the power transfer to a device in an electric current. 2 2-1 Electric current 2-2

More information

Insulators Non-metals are very good insulators; their electrons are very tightly bonded and cannot move.

Insulators Non-metals are very good insulators; their electrons are very tightly bonded and cannot move. SESSION 11: ELECTRIC CIRCUITS Key Concepts Resistance and Ohm s laws Ohmic and non-ohmic conductors Series and parallel connection Energy in an electric circuit X-planation 1. CONDUCTORS AND INSULATORS

More information

CLASS X- ELECTRICITY

CLASS X- ELECTRICITY Conductor- Insulator: Materia Materials through which electric current cannot pass are called insulators. Electric Circuit: A continuous a CLASS X- ELECTRICITY als through which electric current can pass

More information

670 Intro Physics Notes: Electric Current and Circuits

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

More information

Electroscope Used to are transferred to the and Foil becomes and

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.

More information

Chapter 25 Electric Currents and. Copyright 2009 Pearson Education, Inc.

Chapter 25 Electric Currents and. Copyright 2009 Pearson Education, Inc. Chapter 25 Electric Currents and Resistance 25-1 The Electric Battery Volta discovered that electricity could be created if dissimilar metals were connected by a conductive solution called an electrolyte.

More information

Notes on Electricity (Circuits)

Notes on Electricity (Circuits) A circuit is defined to be a collection of energy-givers (active elements) and energy-takers (passive elements) that form a closed path (or complete path) through which electrical current can flow. The

More information

Electric Currents and Circuits

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

More information

Circuits. Electric Current & DC Circuits. Slide 1 / 127. Slide 2 / 127. Slide 3 / 127. Slide 4 / 127. Slide 5 / 127. Slide 6 / 127

Circuits. Electric Current & DC Circuits. Slide 1 / 127. Slide 2 / 127. Slide 3 / 127. Slide 4 / 127. Slide 5 / 127. Slide 6 / 127 Slide 1 / 127 Slide 2 / 127 New Jersey Center for Teaching and Learning Electric Current & DC Circuits www.njctl.org Progressive Science Initiative This material is made freely available at www.njctl.org

More information

National 5 Physics. Language Wikipedia. Electricity

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

More information

Circuits. Circuits. Electric Current & DC Circuits. current and circuits presentation March 22, How to Use this File.

Circuits. Circuits. Electric Current & DC Circuits. current and circuits presentation March 22, How to Use this File. New Jersey Center for Teaching and Learning Electric Current & DC Circuits Progressive Science Initiative This material is made freely available at www.njctl.org and is intended for the non commercial

More information

Ohms Law. V = IR V = voltage in volts (aka potential difference) I = Current in amps R = resistance in ohms (Ω)

Ohms Law. V = IR V = voltage in volts (aka potential difference) I = Current in amps R = resistance in ohms (Ω) Ohms Law V = IR V = voltage in volts (aka potential difference) I = Current in amps R = resistance in ohms (Ω) Current How would you define it? Current the movement of electric charge through a medium

More information

Section 1: Electric Charge and Force

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

More information

Section 1 Electric Charge and Force

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

More information

In this unit, we will examine the movement of electrons, which we call CURRENT ELECTRICITY.

In this unit, we will examine the movement of electrons, which we call CURRENT ELECTRICITY. Recall: Chemistry and the Atom! What are the 3 subatomic Where are they found in the particles? atom? What electric charges do they have? How was a positive ion created? How was a negative ion created?

More information

CHAPTER 1 ELECTRICITY

CHAPTER 1 ELECTRICITY CHAPTER 1 ELECTRICITY Electric Current: The amount of charge flowing through a particular area in unit time. In other words, it is the rate of flow of electric charges. Electric Circuit: Electric circuit

More information

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

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

More information

Electric current is a flow of electrons in a conductor. The SI unit of electric current is ampere.

Electric current is a flow of electrons in a conductor. The SI unit of electric current is ampere. C h a p t e r at G l a n c e 4. Electric Current : Electric current is a flow of electrons in a conductor. The SI unit of electric current is ampere. Current = Charge time i.e, I = Q t The SI unit of charge

More information

1 Written and composed by: Prof. Muhammad Ali Malik (M. Phil. Physics), Govt. Degree College, Naushera

1 Written and composed by: Prof. Muhammad Ali Malik (M. Phil. Physics), Govt. Degree College, Naushera CURRENT ELECTRICITY Q # 1. What do you know about electric current? Ans. Electric Current The amount of electric charge that flows through a cross section of a conductor per unit time is known as electric

More information

Chapter 21 Electric Current and Direct- Current Circuits

Chapter 21 Electric Current and Direct- Current Circuits Chapter 21 Electric Current and Direct- Current Circuits Units of Chapter 21 Electric Current Resistance and Ohm s Law Energy and Power in Electric Circuits Resistors in Series and Parallel Kirchhoff s

More information

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

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

More information

Chapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc.

Chapter 25 Electric Currents and Resistance. Copyright 2009 Pearson Education, Inc. Chapter 25 Electric Currents and Resistance Units of Chapter 25 The Electric Battery Electric Current Ohm s Law: Resistance and Resistors Resistivity Electric Power Units of Chapter 25 Power in Household

More information

Physics Module Form 5 Chapter 2- Electricity GCKL 2011 CHARGE AND ELECTRIC CURRENT

Physics Module Form 5 Chapter 2- Electricity GCKL 2011 CHARGE AND ELECTRIC CURRENT 2.1 CHARGE AND ELECTRIC CURRENT Van de Graaf 1. What is a Van de Graaff generator? Fill in each of the boxes the name of the part shown. A device that produces and store electric charges at high voltage

More information

NATIONAL 5 PHYSICS ELECTRICITY

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

More information

EXPERIMENT 12 OHM S LAW

EXPERIMENT 12 OHM S LAW EXPERIMENT 12 OHM S LAW INTRODUCTION: We will study electricity as a flow of electric charge, sometimes making analogies to the flow of water through a pipe. In order for electric charge to flow a complete

More information

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

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:

More information

1. What is heating effect of current? What is its cause?

1. What is heating effect of current? What is its cause? GRADE: X PHYSICS (ELECTRICITY) DOMESTIC ELECTRIC CIRCUITS: SERIES OR PARALLEL Disadvantages of series circuits for domestic wiring : In series circuit, if one electrical appliance stops working, due to

More information

Electric Current. Chapter 17. Electric Current, cont QUICK QUIZ Current and Resistance. Sections: 1, 3, 4, 6, 7, 9

Electric Current. Chapter 17. Electric Current, cont QUICK QUIZ Current and Resistance. Sections: 1, 3, 4, 6, 7, 9 Electric Current Chapter 17 Current and Resistance Sections: 1, 3, 4, 6, 7, 9 Whenever electric charges of like signs move, an electric current is said to exist The current is the rate at which the charge

More information

Chapter 20: Electric Current, Resistance & Ohm s Law. Brent Royuk Phys-112 Concordia University

Chapter 20: Electric Current, Resistance & Ohm s Law. Brent Royuk Phys-112 Concordia University Chapter 20: Electric Current, Resistance & Ohm s Law Brent Royuk Phys-112 Concordia University The Minds of Our Own Challenge Light a bulb with a battery and a wire. Could you do it? 2 Introduction Batteries

More information

Ohm s Law and Electronic Circuits

Ohm s Law and Electronic Circuits Production Ohm s Law and Electronic Circuits Page 1 - Cyber Security Class ELECTRICAL CIRCUITS All you need to be an inventor is a good imagination and a pile of junk. -Thomas Edison Page 2 - Cyber Security

More information

Electric Currents and Circuits

Electric Currents and Circuits Nicholas J. Giordano www.cengage.com/physics/giordano Chapter 19 Electric Currents and Circuits Marilyn Akins, PhD Broome Community College Electric Circuits The motion of charges leads to the idea of

More information

Electricity Courseware Instructions

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

More information

Electricity. Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2. onedio.com

Electricity. Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2. onedio.com Electricity Lily, Laura, Lynette, Elyse, Gillian, Emma, Hailey Period 2 onedio.com Electrostatics vs. Electricity Electrostatics is the study of charges at rest Electrostatics: to help remember the difference

More information

Electric Currents and Simple Circuits

Electric Currents and Simple Circuits -1 Electric Currents and Simple Circuits Electrons can flow along inside a metal wire if there is an E-field present to push them along ( F= qe). The flow of electrons in a wire is similar to the flow

More information

Chapter 20: Electric Current, Resistance & Ohm s Law

Chapter 20: Electric Current, Resistance & Ohm s Law Chapter 0: Electric Current, Resistance & Brent Royuk Phys-11 Concordia University The Minds of Our Own Challenge Light a bulb with a battery and a wire. Could you do it? Introduction Batteries supply

More information

Electric Current Unlike static electricity, electric current is a continuous flow of charged particles (electricity). For current to flow, there must

Electric Current Unlike static electricity, electric current is a continuous flow of charged particles (electricity). For current to flow, there must CURRENT ELECTRICITY Electric Current Unlike static electricity, electric current is a continuous flow of charged particles (electricity). For current to flow, there must be a power source and there must

More information

52 VOLTAGE, CURRENT, RESISTANCE, AND POWER

52 VOLTAGE, CURRENT, RESISTANCE, AND POWER 52 VOLTAGE, CURRENT, RESISTANCE, AND POWER 1. What is voltage, and what are its units? 2. What are some other possible terms for voltage? 3. Batteries create a potential difference. The potential/voltage

More information

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

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

More information

Chapter 7 Direct-Current Circuits

Chapter 7 Direct-Current Circuits Chapter 7 Direct-Current Circuits 7. Introduction... 7. Electromotive Force... 7.3 Resistors in Series and in Parallel... 4 7.4 Kirchhoff s Circuit Rules... 6 7.5 Voltage-Current Measurements... 8 7.6

More information

Current Electricity.notebook. December 17, 2012

Current Electricity.notebook. December 17, 2012 1 Circuit Diagrams and Assembly 1. Draw a circuit diagram containing a battery, a single throw switch, and a light. 2. Once the diagram has been checked by your teacher, assemble the circuit. Keep the

More information

Review. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

Review. Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. Review Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1. When more devices are added to a series circuit, the total circuit resistance: a.

More information

Chapter 18 Electric Currents

Chapter 18 Electric Currents Chapter 18 Electric Currents 1 The Electric Battery Volta discovered that electricity could be created if dissimilar metals were connected by a conductive solution called an electrolyte. This is a simple

More information

Equivalent resistance in Series Combination

Equivalent resistance in Series Combination Combination of Resistances There are two methods of joining the resistors together. SERIES CONNECTION An electric circuit in which three resistors having resistances R1, R2 and R3, respectively, are joined

More information

This week. 3/23/2017 Physics 214 Summer

This week. 3/23/2017 Physics 214 Summer This week Electrical Circuits Series or parallel that s the question. Current, Power and Energy Why does my laptop battery die? Transmission of power to your home Why do we have big transmission towers?

More information

This week. 6/2/2015 Physics 214 Summer

This week. 6/2/2015 Physics 214 Summer This week Electrical Circuits Series or parallel that s the question. Current, Power and Energy Why does my laptop battery die? Transmission of power to your home Why do we have big transmission towers?

More information

Electricity Test Review

Electricity Test Review Electricity Test Review Definitions; Series Circuit, Parallel Circuit, Equivalent Resistance, Fuse, Circuit Breaker, kilowatt hour, load, short circuit, dry cell, wet cell, fuel cells, solar cells, fossil

More information

Test Review Electricity

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

More information

Electricity Final Unit Final Assessment

Electricity Final Unit Final Assessment Electricity Final Unit Final Assessment Name k = 1/ (4pe 0 ) = 9.0 10 9 N m 2 C -2 mass of an electron = 9.11 10-31 kg mass of a proton = 1.67 10-27 kg G = 6.67 10-11 N m 2 kg -2 C = 3 x10 8 m/s Show all

More information

LABORATORY 4 ELECTRIC CIRCUITS I. Objectives

LABORATORY 4 ELECTRIC CIRCUITS I. Objectives LABORATORY 4 ELECTRIC CIRCUITS I Objectives to be able to discuss potential difference and current in a circuit in terms of electric field, work per unit charge and motion of charges to understand that

More information

EE301 RESISTANCE AND OHM S LAW

EE301 RESISTANCE AND OHM S LAW Learning Objectives a. Describe the concept of resistance b. Use Ohm s law to calculate current, voltage, and resistance values in a circuit c. Discuss the difference between an open circuit and a short

More information

p I = Q (charge) t (time)

p I = Q (charge) t (time) ClXB-B-ElfT I M C T R I C I T Y 3-08 *Demonstrate and explain how static and current electricity are alike and different Vocabulary: discharge, circuit, circuit diagram, switch, dry cell, battery, load,

More information

CHAPTER 20 ELECTRIC CIRCUITS

CHAPTER 20 ELECTRIC CIRCUITS CHAPTER 20 ELECTRIC CIRCUITS PROBLEMS. SSM REASONING Since current is defined as charge per unit time, the current used by the portable compact disc player is equal to the charge provided by the battery

More information

Chapter 17 Electric Current and Resistance Pearson Education, Inc.c

Chapter 17 Electric Current and Resistance Pearson Education, Inc.c Chapter 17 Electric Current and Resistance 2010 Pearson Education, Inc.c 1 Units of Chapter 17 Batteries and Direct Current Current and Drift Velocity Resistance and Ohm s Law Electric Power 2010 Pearson

More information

Electric charge is conserved the arithmetic sum of the total charge cannot change in any interaction.

Electric charge is conserved the arithmetic sum of the total charge cannot change in any interaction. Electrostatics Electric charge is conserved the arithmetic sum of the total charge cannot change in any interaction. Electric Charge in the Atom Atom: Nucleus (small, massive, positive charge) Electron

More information

Electric Circuits. June 12, 2013

Electric Circuits. June 12, 2013 Electric Circuits June 12, 2013 Definitions Coulomb is the SI unit for an electric charge. The symbol is "C". Electric Current ( I ) is the flow of electrons per unit time. It is measured in coulombs per

More information

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. 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

More information

Nama :.. Kelas/No Absen :

Nama :.. Kelas/No Absen : Nama :.. Kelas/No Absen : TASK 2 : CURRENT AND RESISTANCE 1. A car battery is rated at 80 A h. An ampere-hour is a unit of: A. power B. energy C. current D. charge E. force 2. Current has units: A. kilowatt-hour

More information

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

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

More information

DC Circuits. Circuits and Capacitance Worksheet. 10 Ω resistance. second? on the sodium is the same as on an electron, but positive.

DC Circuits. Circuits and Capacitance Worksheet. 10 Ω resistance. second? on the sodium is the same as on an electron, but positive. Circuits and Capacitance Worksheet DC Circuits 1. A current of 1.30 A flows in a wire. How many electrons are flowing past any point in the wire per second? 2. What is the current in amperes if 1200 Na

More information

Notes: Ohm s Law and Electric Power

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

More information

Resistance Learning Outcomes. Resistance Learning Outcomes. Resistance

Resistance Learning Outcomes. Resistance Learning Outcomes. Resistance Resistance Learning Outcomes Define resistance and give its unit. Solve problems about resistance. State Ohm s Law. HL: Derive the formulas for resistors in series and parallel. Solve problems about resistors

More information

Chapter 17. Current and Resistance. Sections: 1, 3, 4, 6, 7, 9

Chapter 17. Current and Resistance. Sections: 1, 3, 4, 6, 7, 9 Chapter 17 Current and Resistance Sections: 1, 3, 4, 6, 7, 9 Equations: 2 2 1 e r q q F = k 2 e o r Q k q F E = = I R V = A L R ρ = )] ( 1 [ o o T T + = α ρ ρ V I V t Q P = = R V R I P 2 2 ) ( = = C Q

More information

physics 4/7/2016 Chapter 31 Lecture Chapter 31 Fundamentals of Circuits Chapter 31 Preview a strategic approach THIRD EDITION

physics 4/7/2016 Chapter 31 Lecture Chapter 31 Fundamentals of Circuits Chapter 31 Preview a strategic approach THIRD EDITION Chapter 31 Lecture physics FOR SCIENTISTS AND ENGINEERS a strategic approach THIRD EDITION randall d. knight Chapter 31 Fundamentals of Circuits Chapter Goal: To understand the fundamental physical principles

More information

PHYSICS FORM 5 ELECTRICAL QUANTITES

PHYSICS FORM 5 ELECTRICAL QUANTITES QUANTITY SYMBOL UNIT SYMBOL Current I Amperes A Voltage (P.D.) V Volts V Resistance R Ohm Ω Charge (electric) Q Coulomb C Power P Watt W Energy E Joule J Time T seconds s Quantity of a Charge, Q Q = It

More information

Part 4: Electricity & Magnetism

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

More information

3 Electric current, resistance, energy and power

3 Electric current, resistance, energy and power 3 3.1 Introduction Having looked at static charges, we will now look at moving charges in the form of electric current. We will examine how current passes through conductors and the nature of resistance

More information

Material World Electricity and Magnetism

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

More information

ELECTRIC CURRENTS D R M A R T A S T A S I A K D E P A R T M E N T O F C Y T O B I O L O G Y A N D P R O T E O M I C S

ELECTRIC CURRENTS D R M A R T A S T A S I A K D E P A R T M E N T O F C Y T O B I O L O G Y A N D P R O T E O M I C S ELECTRIC CURRENTS D R M A R T A S T A S I A K D E P A R T M E N T O F C Y T O B I O L O G Y A N D P R O T E O M I C S lecture based on 2016 Pearson Education, Ltd. The Electric Battery Electric Current

More information

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

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.

More information

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

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.

More information