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


 Moses Newman
 4 years ago
 Views:
Transcription
1 Slide 1 / 127 Slide 2 / 127 Electric Current & DC Circuits Slide 3 / 127 How to Use this File Slide 4 / 127 Electric Current & DC Circuits Each topic is composed of brief direct instruction There are formative assessment questions after every topic denoted by black text and a number in the upper left. > Students work in groups to solve these problems but use student responders to enter their own answers. > Designed for SMART Response PE student response systems. > Use only as many questions as necessary for a sufficient number of students to learn a topic. Full information on how to teach with NJCTL courses can be found at njctl.org/courses/teaching methods Circuits Conductors Resistivity and Resistance Circuit Diagrams Measurement EMF & Terminal oltage Kirchhoff's Rules Capacitors RC Circuits Click on the topic to go to that section Slide 5 / 127 Slide 6 / 127 Electric Current Circuits Electric Current is the rate of flow of electric charges (charge carriers) through space. More specifically, it is defined as the amount of charge that flows past a location in a material per unit time. The letter "I" is the symbol for current. I = ΔQ Δt ΔQ is the amount of charge, and Δt is the time it flowed past the location. Return to Table of Contents The current depends on the type of material and the Electric Potential difference (voltage) across it.
2 Slide 7 / 127 Electric Current Slide 8 / 127 Electric Current A good analogy to help understand Electric Current is to consider water flow. The flow of water molecules is similar to the flow of electrons (the charge carriers) in a wire. The current, I = ΔQ Δt has the units Coulombs per second. Water flow depends on the pressure exerted on the molecules either by a pump or by a height difference, such as water falling off a cliff. Electric current depends on the "pressure" exerted by the Electric Potential difference  the greater the Electric Potential difference, the greater the Electric Current. The units can be rewritten as Amperes (A). Amperes are often called "amps". 1 A = 1 C/s Slide 9 / 127 Electric Current Slide 10 / 127 Electric Current We know that if an Electric Potential difference is applied to a wire, charges will flow from high to low potential  a current. However, due to a convention set by Benjamin Franklin, current in a wire is defined as the movement of positive charges (not the electrons which are really moving) and is called "conventional current." Benjamin Franklin didn't do this to confuse future generations of electrical engineers and students. It was already known that electrical phenomena came in two flavors  attractive and repulsive  Franklin was the person who explained them as distinct positive and negative charges. He arbitrarily assigned a positive charge to a glass rod that had been rubbed with silk. He could just as easily called it negative  50/50 chance. The glass rod was later found to have a shortage of electrons (they were transferred to the silk). So if the glass rod is grounded, the electrons will flow from the ground to the rod. The problem comes in how Electric Potential is defined  charge carriers will be driven from high to low potential  from positive to negative. For this to occur in the glass rod  ground system, the conventional current will flow from the rod to the ground  opposite the direction of the movement of electrons. Slide 11 / 127 Electric Current To summarize  conventional Electric Current is defined as the movement of positive charge. In wires, it is opposite to the direction of the electron movement. However  in the case of a particle accelerator, where electrons are stripped off of an atom, resulting in a positively charged ion, which is then accelerated to strike a target  the direction of the conventional current is the same as the direction of the positive ions! An electric circuit is an external path that charges can follow between two terminals using a conducting material. For charge to flow, the path must be complete and unbroken. Slide 12 / 127 Circuits An example of a conductor used to form a circuit is copper wire. Continuing the water analogy, one can think of a wire as a pipe for charge to move through.
3 Slide 13 / C of charge passes a location in a circuit in 10 seconds. What is the current flowing past the point? Slide 13 () / C of charge passes a location in a circuit in 10 seconds. What is the current flowing past the point? Slide 14 / A circuit has 3 A of current. How long does it take 45 C of charge to travel through the circuit? Slide 14 () / A circuit has 3 A of current. How long does it take 45 C of charge to travel through the circuit? Slide 15 / A circuit has 2.5 A of current. How much charge travels through the circuit after 4s? Slide 15 () / A circuit has 2.5 A of current. How much charge travels through the circuit after 4s?
4 Each battery has two terminals which are conductors. The terminals are used to connect an external circuit allowing the movement of charge. Batteries convert chemical energy to electrical energy which maintains the potential difference. The chemical reaction acts like an escalator, carrying charge up to a higher voltage. Slide 16 / 127 Batteries Click here for a Battery oltage Simulation from PhET Positive Terminal Negative Terminal Slide 17 / 127 Reviewing Basic Circuits The circuit cannot have gaps. The bulb had to be between the wire and the terminal. A voltage difference is needed to make the bulb light. The bulb still lights regardless of which side of the battery you place it on. As you watch the video,observations and the answers to the questions below. What is going on in the circuit? What is the role of the battery? How are the circuits similar? different? Click here for video using the circuit simulator from PhET Slide 18 / 127 Slide 19 / 127 Batteries and Current The battery pushes current through the circuit. A battery acts like a pump, pushing charge through the circuit. It is the circuit's energy source. Conductors Charges do not experience an electrical force unless there is a difference in electrical potential (voltage).therefore, batteries have a potential difference between their terminals. The positive terminal is at a higher voltage than the negative terminal. click here for a video from eritasium's Derek on current How will voltage affect current? Return to Table of Contents Slide 20 / 127 Conductors Some conductors "conduct" better or worse than others. Reminder: conducting means a material allows for the free flow of electrons. The flow of electrons is just another name for current. Another way to look at it is that some conductors resist current to a greater or lesser extent. We call this resistance, R. Resistance is measured in ohms which is noted by the Greek symbol omega (Ω) Slide 21 / 127 Current vs Resistance & oltage Raising resistance reduces current. Raising voltage increases current. We can combine these relationships in what we call "Ohm's Law". I = R Another way to write this is that: R = I OR = IR How will resistance affect current? Click here to run another PhET simulation You can see that one # = A click here for a eritasium music video on electricity
5 Slide 22 / 127 Current vs Resistance & oltage Raising resistance reduces current and raising voltage increases current. However, this relationship is linear in only what we call Ohmic resistors. If the relationship is not linear, it is a nonohmic resistor. Slide 23 / A flashlight has a resistance of 25 # and is connected by a wire to a 120 source of voltage. What is the current in the flashlight? oltage NonOhmic Ohmic Current Slide 23 () / A flashlight has a resistance of 25 # and is connected by a wire to a 120 source of voltage. What is the current in the flashlight? Slide 24 / How much voltage is needed in order to produce a 0.70 A current through a 490 # resistor? Slide 24 () / 127 Slide 25 / What is the resistance of a rheostat coil, if 0.05 A of current flows through it when 6 is applied across it?
6 Slide 25 () / What is the resistance of a rheostat coil, if 0.05 A of current flows through it when 6 is applied across it? Slide 26 / 127 Electrical Power Power is defined as work per unit time P = W t if W = Q then substitute: if I = Q then substitute: t P = Q t P = I What happens if the current is increased? What happens if the voltage is decreased? Slide 27 / 127 Electrical Power Slide 28 / 127 Electrical Power Let's think about this another way... The water at the top has GPE & KE. As the water falls, it loses GPE and the wheel gets turned, doing work.when the water falls to the bottom it is now slower, having done work. Electric circuits are similar. A charge falls from high voltage to low voltage. In the process of falling energy may be used (light bulb, run a motor, etc). What is the unit of Power? Slide 29 / 127 Electrical Power How can we rewrite electrical power by using Ohm's Law? (electrical power) P = I P = R P = 2 R (Ohm's Law) I = R Slide 30 / 127 Is there yet another way to rewrite this? (electrical power) P = I Electrical Power I = can be rewritten as = IR. R P = I(IR) P = I 2 R (Ohm's Law) = I R We can substitute this into Power
7 Slide 31 / 127 Batteries D, C, AA, & AAA have the same voltage, however they differ in the amount of power they deliver. Slide 32 / A toy car's electric motor has a resistance of 17 # ; find the power delivered to it by a 6 battery. D C AAA AA For instance, D batteries can deliver more current and therefore more power. Slide 32 () / A toy car's electric motor has a resistance of 17 # ; find the power delivered to it by a 6 battery. Slide 33 / What is the power consumption of a flash light bulb that draws a current of 0.28 A when connected to a 6 battery? Slide 33 () / What is the power consumption of a flash light bulb that draws a current of 0.28 A when connected to a 6 battery? Slide 34 / A 30Ω toaster consumes 560 W of power: how much current is flowing through the toaster?
8 Slide 34 () / 127 Slide 35 / When 30 is applied across a resistor it generates 600 W of heat: what is the magnitude of its resistance? Slide 35 () / 127 Slide 36 / When 30 is applied across a resistor it generates 600 W of heat: what is the magnitude of its resistance? Resistivity and Resistance Return to Table of Contents Slide 37 / 127 "Pipe" size Slide 37 () / 127 "Pipe" size How could the wire in the circuit affect the current? If wire is like a pipe, and current is like water that flows through the pipe... if there were pipes with water in them, what could we do to the pipes to change the speed of the water (the current)? How could the wire in the circuit affect the current? If wire is like a pipe, and current is like water that flows change through the crosssectional area of the pipe... the pipe making it bigger will allow more water to flow if there were pipes with water in them, what could we do to the change the length of the pipe pipes to change the speed of the increasing the length will water (the current)? increase the time it takes for the water to get to the end of its trip
9 Slide 38 / 127 Resistivity & Resisitance Every conductor "conducts" electric charge to a greater or lesser extent. The last example also applies to conductors like copper wire. Decreasing the length (L) or increasing the crosssectional area (A) would increase conductivity. Also, the measure of a conductor's resistance to conduct is called its resistivity. Each material has a different resistivity. Resistivity is abbreviated using the Greek letter rho (#). Combining what we know about A, L, and ρ, we can find a conductor's total resistance. Slide 39 / 127 Resistivity & Resisitance Resistance, R, is measured in Ohms (Ω). Ω is the Greek letter Omega. Crosssectional area, A, is measured in m 2 Length, L, is measured in m R = #L A Resistivity, ρ, is measured in Ωm How can we define A for a wire? R = #L A What is the resistance of a good conductor? Low; low resistance means that electric charges are free to move in a conductor. Click here for a PhET simulation about Resistance Slide 40 / 127 Resisitance # = RA L Slide 42 / Rank the following materials in order of best conductor to worst conductor. Slide 41 / 127 Resistivities of Common Conductors Material Silver Copper Gold Aluminum Tungsten Iron Platinum Mercury Nichrome Resistivity (108 Ωm) Slide 42 () / Rank the following materials in order of best conductor to worst conductor. A Iron, Copper, Platinum A Iron, Copper, Platinum B Platinum, Iron, Copper Material Resistivity (108 Ωm) B Platinum, Iron, Copper Material Resistivity (108 Ωm) C Copper, Iron, Platinum Silver Copper C Copper, Iron, Platinum Silver Copper Gold 2.44 Gold 2.44 Aluminum 2.65 Aluminum 2.65 Tungsten Iron Platinum Mercury Tungsten Iron Platinum Mercury C Nichrome 100 Nichrome 100
10 Slide 43 / 127 Slide 43 () / What is the resistance of a 2 m long copper wire whose crosssectional area of 0.2 mm 2? 2r Slide 44 / The following resistors are made of the same material. Rank them from greatest resistance to least resistance. L 2r 2L R w R x R y R z r L r 2L 2r Slide 44 () / The following resistors are made of the same material. Rank them from greatest resistance to least resistance. L 2r 2L R w R x R y R z r L r 2L A R x > R w > R z > R y B R z > R y > R x > R w C Ry > R z > R w > R x A R x > R w > R z > R y B R z > R y > R x > R w C Ry > R z > R w > R x B D R y > R w > R z > R x D R y > R w > R z > R x Slide 45 / What diameter of 100 m long copper wire would have a resistance of 0.10 #? Slide 45 () / What diameter of 100 m long copper wire would have a resistance of 0.10 #?
11 Slide 46 / 127 Slide 46 () / The length of a copper wire is cut to half. By what factor does the resistance change? 15 The length of a copper wire is cut to half. By what factor does the resistance change? A 1/4 B 1/2 C 2 D 4 A 1/4 B 1/2 C 2 D 4 B Slide 47 / 127 Slide 47 () / The radius of a copper wire is doubled. By what factor does the resistivity change? 16 The radius of a copper wire is doubled. By what factor does the resistivity change? A 1/4 B 1/2 C 1 D 2 A 1/4 B 1/2 C 1 D 2 C Slide 48 / 127 Slide 49 / 127 Circuit Diagrams Circuit Diagrams Drawing realistic pictures of circuits can be very difficult. For this reason, we have common symbols to represent each piece. Resistor Battery Wire Return to Table of Contents *Note: Circuit diagrams do not show where each part is physically located.
12 Slide 50 / 127 Circuit Diagrams Draw a simple circuit that has a 9 battery with a 3 Ω resistor across its terminals. What is the magnitude and direction of the current? Slide 50 () / 127 Circuit Diagrams Draw a simple circuit that has a 9 battery with a 3 Ω resistor across its terminals. What is the magnitude and direction of the current? R = 3# I = 3A I = 9 Conventional current flows from the positive terminal to the negative terminal. Slide 51 / 127 Circuit Diagrams There are two ways to add a second resistor to the circuit. Conventional current flows from the positive terminal to the negative terminal. Slide 52 / 127 Circuit Diagrams Are the following sets of resistors in series or parallel? Series Parallel R 1 R 1 R 1 R 1 R 2 R 2 R 2 R 2 All charges must move through both resistors to get to the negative terminal. Charges pass through either R 1 or R 2 but not both. Slide 52 () / 127 Circuit Diagrams Are the following sets of resistors in series or parallel? R R 1 1 Slide 53 / 127 Equivalent Resistance Resistors and voltage from batteries determine the current. R 2 R 2 Circuits can be redrawn as if there were only a single resistor and battery.by reducing the circuit this way, the circuit becomes easier to study. The process of reducing the resistors in a circuit is called finding the equivalent resistance (R eq). R1 R2 Series Parallel The "test" is to trace the shortest route around the circuit. The resistors found on the same route are in series; those not found on the same route are in parallel to those that were.
13 Slide 54 / 127 Series Circuits: Equivalent Resistance Slide 54 () / 127 Series Circuits: Equivalent Resistance R1 R2 R1 R2 What happens to the current in the circuit to the right? What happens to the current in the circuit to the right? The current passing through all parts of a series circuit is the same. For example: I = I 1 = I 2 Slide 55 / 127 Series Circuits: Equivalent Resistance Slide 55 () / 127 Series Circuits: Equivalent Resistance R1 R2 R1 R2 What happens to the voltage as it moves around the circuit? What happens to the voltage as it moves around the circuit? The sum of the voltage drops across each of the resistors in a series circuit equals the voltage of the battery. For example: = 1 2 Slide 56 / 127 Series Circuits: Equivalent Resistance Slide 57 / What is the equivalent resistance in this circuit? If = IR = I 1R 1 I 2R 2 I 3R 3 IR = IR 1 IR 2 IR 3 substitute Ohm's Law solved for is: = IR but since current (I) is the same everywhere in a series circuit, I = I 1 = I 2 = I 3 R 1 = 5# R2 = 3# R eq = R 1 R 2 R 3... Now divide by I = 9 To find the equivalent resistance (R eq) of a series circuit, add the resistance of all the resistors.if you add more resistors to a series circuit, what happens to the resistance?
14 Slide 57 () / What is the equivalent resistance in this circuit? Slide 58 / What is the total current at any spot in the circuit? R 1 = 5# R2 = 3# R 1 = 5# R 2 = 3# Resistors in series: = 9 = 9 Slide 58 () / What is the total current at any spot in the circuit? Slide 59 / What is the voltage drop across R 1? R 1 = 5# R 2 = 3# R 1 = 5# R 2 = 3# Resistors in series: = 9 = 9 Slide 59 () / What is the voltage drop across R 1? Slide 60 / What is the voltage drop across R 2? R 1 = 5# R 2 = 3# Resistors in series: R 1 = 5# R 2 = 3# = 9 Net Current/equal everywhere: oltage Drop across R 1: = 9 hint: A good way to check your work is to see if the voltage drop across all resistors equals the total voltage in the circuit.
15 Slide 60 () / What is the voltage drop across R 2? Slide 61 / How much power is used by R 1? R 1 = 5# R 2 = 3# Net Current/equal everywhere: Resistors in series: R 1 = 5# R 2 = 3# = 9 oltage Drop across R 2: = 9 hint: A good way to check your work [This is object to see is a if pull the tab] voltage drop across all resistors equals the total voltage in the circuit. Slide 61 () / 127 Slide 62 / 127 Parallel Circuits: Equivalent Resistance R 1 What happens to the current in the circuit to the right? R 2 Slide 62 () / 127 Parallel Circuits: Equivalent Resistance Slide 63 / 127 Parallel Circuits: Equivalent Resistance R 1 R 1 What happens to the current in the circuit to the right? R 2 What happens to the voltage as it moves around the circuit? R 2 The sum of the currents through each of the resistors in a parallel circuit equals the current of the battery. For example: I = I 1 I 2
16 Slide 63 () / 127 Parallel Circuits: Equivalent Resistance Slide 64 / 127 Parallel Circuits: Equivalent Resistance R 1 If I = I1 I2 I3 Rewrite Ohm's Law for I and substitute for each resistor What happens to the voltage as it moves around the circuit? R 2 R = 1 R1 2 R2 3 R3 Also, since = 1 = 2 = 3 so we can substitute for any other voltage The voltage across all the resistors in a parallel circuit is the same. For example: = 1 = 2 R R 1 = Req = = ( 1 R1 R1 1 R1 R2 1 R2 1 R2 1 R3 R3 1 R3 ( oltage is a common factor, so factor it out! Divide by to eliminate voltage from the equation. Slide 65 / 127 If you add more resistors in parallel, what will happen the to resistance of the circuit? Slide 65 () / What is the equivalent resistance in the circuit? 22 What is the equivalent resistance in the circuit? = 18 = 18 Slide 66 / What is the voltage at any spot in the circuit? Slide 66 () / What is the voltage at any spot in the circuit? 18 = 18 = 18
17 Slide 67 / What is the current through R 1? Slide 67 () / What is the current through R 1? = 18 = 18 Slide 68 / What is the current through R 2? Slide 68 () / What is the current through R 2? = 18 = 18 Slide 69 / What is the power used by R 1? Slide 69 () / What is the power used by R 1? Power used by R 1: = 18 = 18
18 Slide 70 / What is the power used by R 2? Slide 70 () / What is the power used by R 2? Power used by R 2: = 18 = 18 Slide 71 / What is the total current in this circuit? Slide 71 () / What is the total current in this circuit? R 3 = 4# R 3 = 4# = 18 = 18 Slide 72 / What is the voltage drop across the third resistor? Slide 72 () / What is the voltage drop across the third resistor? R 3 = 4# R 3 = 4# = 18 = 18
19 Slide 73 / What is the current though the first resistor? Slide 73 () / What is the current though the first resistor? R 3 = 4# R 3 = 4# = 18 = 18 Slide 74 / 127 Slide 74 () / Which two of the following sets of resistors have the same equivalent resistance? Select two answers. 31 Which two of the following sets of resistors have the same equivalent resistance? Select two answers. A 3Ω B 4Ω A 3Ω B 4Ω 6Ω 4Ω 6Ω 4Ω A, D C 3Ω 6Ω D 1Ω 1Ω C 3Ω 6Ω D 1Ω 1Ω Slide 75 / 127 Slide 76 / 127 oltmeter Measurement oltage is measured with a voltmeter. oltmeters are connected in parallel and measure the difference in potential between two points. Return to Table of Contents Since circuits in parallel have the same voltage, and a voltmeter has very high resistance, very little current passes through it. This means that it has little effect on the circuit.
20 Slide 77 / 127 Ammeter Slide 78 / 127 Multimeter Current is measured using an ammeter. Ammeters are placed in series with a circuit. In order to not interfere with the current, the ammeter has a very low resistance. Although there are separate items to measure current and voltage, there are devices that can measure both (one at a time). These devices are called multimeters.multimeters can also measure resistance. Click here for a PhET simulation on circuits Slide 79 / 127 Slide 79 () / A group of students prepare an experiment with electric circuits. Which of the following diagrams can be used to measure both current and voltage? L 32 A group of students prepare an experiment with electric circuits. Which of the following diagrams can be used to measure both current and voltage? L A B A B C D C D E E E Slide 80 / 127 Slide 81 / 127 Electromotive Force EMF & Terminal oltage Return to Table of Contents r R eq E _ A battery is a source of voltage AND a resistor. Each battery has a source of electromotive force and internal resistance. Electromotive force (EMF) is the process that carries charge from low to high voltage. Another way to think about it is that EMF is the voltage you measure when no resistance is connected to the circuit.
21 Slide 82 / 127 Electromotive Force Slide 83 / 127 Terminal oltage r R eq E _ Terminal voltage ( T) is the voltage measured when a voltmeter is across its terminals. If there is no circuit attached, no current flows, and the measurement will equal the EMF. r R eq E _ We say that the terminal voltage is: T = E  Ir Maximum current will occur when there is zero external current. If however a circuit is attached, the internal resistance will result in a voltage drop, and a smaller terminal voltage. (E  Ir) When solving for equivalent resistance in a circuit, the internal resistance of the battery is considered a series resistor. R EQ = R int R ext Slide 84 / When the switch in the circuit below is open, the voltmeter reading is referred to as: Slide 84 () / When the switch in the circuit below is open, the voltmeter reading is referred to as: A EMF B Current C Power D Terminal oltage E Restivity A EMF B Current C Power D Terminal oltage E Restivity A Slide 85 / When the switch in the circuit below is closed, the voltmeter reading is referred to as: Slide 85 () / When the switch in the circuit below is closed, the voltmeter reading is referred to as: A Terminal oltage B EMF C Current D Resistance E Power A Terminal oltage B EMF C Current D Resistance E Power A
22 Slide 86 / 127 Slide 86 () / A 6 battery, whose internal resistance 1.5 Ω is connected in series to a light bulb with a resistance of 6.8 Ω. What is the current in the circuit? Slide 87 / 127 Slide 87 () / A 6 battery, whose internal resistance 1.5Ω is connected in series to a light bulb with a resistance of 6.8Ω. What is the terminal voltage of the battery? Slide 88 / 127 Slide 88 () / A 25 Ω resistor is connected across the terminals of a battery whose internal resistance is 0.6 Ω. What is the EMF of the battery if the current in the circuit is 0.75 A?
23 Slide 89 / 127 Slide 90 / 127 Kirchhoff's Rules Kirchhoff's Rules Up until this point we have been analyzing simple circuits by combining resistors in series and parallel and using Ohm's law. This works for simple circuits but in order analyze more complex circuits we need to use Kirchhoff's Rules which are based on the laws of conservation of charge and energy. Return to Table of Contents Slide 91 / 127 Slide 92 / 127 Kirchhoff's First rule, or junction rule is based on the law of conservation of charge. It states: At any junction point, the sum of all currents entering the junction point must equal the sum of all the currents exiting the junction. For example, I 1 I 2 = I 3 Kirchhoff's Rules I 3 I 1 I 2 Kirchhoff's Second rule, or loop rule is based on the law of conservation of energy. It states: The sum of all changes in potential around any closed path must equal zero. For example, Kirchhoff's Rules The sum of the voltage drops is equal to the voltage across the battery =0 OR = Label and  for each battery. Slide 93 / 127 Problem Solving with Kirchhoff's Rules 2. Label the current in each branch with a symbol and an arrow. (Don't worry about the direction of the arrow. It it's incorrect the solution will be negative.) 3. Apply the junction rule to each junction. You need as many equations as there are unknowns. (You can also use Ohm's Law to reduce the number of unknowns.) 4. Apply the loop rule for each loop. (Pay attention to signs. For a resistor, the potential difference is negative. For a battery the potential difference is positive.) Slide 94 / 127 Problem Solving with Kirchhoff's Rules Find the unknowns in the following circuit: I2 = 2.6 A R1 = 5# R2 = 3# R3 =? R4 = 2# 3 = 1.87 = Solve the equations algebraically.
24 Slide 95 / 127 Problem Solving with Kirchhoff's Rules First, label and  for each battery. I2 = 2.6 A Slide 96 / 127 Problem Solving with Kirchhoff's Rules Next, label the current in each branch with a symbol and an arrow. I1 I2 = 2.6 A R1 = 5# R2 = 3# R3 =? R4 = 2# 3 = 1.87 _ = 12 I3 R1 = 5# R2 = 3# I4 R3 =? R4 = 2# 3 = 1.87 _ = 12 I Slide 97 / 127 Slide 97 () / 127 Problem Solving with Kirchhoff's Rules Next, apply the junction rule to each junction. Problem Solving with Kirchhoff's Rules Next, apply the junction rule to each junction. I1 I2 = 2.6 A I1 I2 = 2.6 A R1 = 5# R2 = 3# R1 = 5# R2 = 3# I3 I4 R3 =? R4 = 2# 3 = 1.87 _ = 12 I I3 I4 R3 =? = R4 = I 2# = I 3 I 4 I 2 3 = 1.87 I 1 = I 3 _ = 12 I Slide 98 / 127 Slide 98 () / 127 Problem Solving with Kirchhoff's Rules Next, apply the loop rule to each loop. Problem Solving with Kirchhoff's Rules Next, apply the loop rule to each loop. I1 I2 = 2.6 A I1 I2 = 2.6 A R1 = 5# R2 = 3# R1 = 5# R2 = 3# I3 I4 R3 =? R4 = 2# 3 = 1.87 _ = 12 I I3 I4 = R3 =? R4 = 2# 3 = 1.87 = _ = 4 = 12 I I = I 3 I 4 I = I 2 I 1 = I 3 I = I 3 I 4 I = I 2 I 1 = I 3
25 Slide 99 / 127 Problem Solving with Kirchhoff's Rules Slide 100 / 127 Problem Solving with Kirchhoff's Rules List the givens and use ohm's law to solve for the unknowns. Find the unknowns in the following circuit: R3 = 2 # Current (Amps) oltage (olts) Resistance (Ohms) R1 5 R R R4 2 Total 12 R1 = 10?# I1 = 7 A 1 = 70? R2 = 23?# I2 = 3 A 2 = 70? I3 = 10 A 3 = 20? R4 = 3 # I4 = 10? A 4 = 30? I = I 3 I 4 I = I 2 I 1 = I 3 = = = 4 = 120 Slide 101 / 127 Capacitors Slide 102 / 127 Capacitance When a battery is connected to a capacitor, charge moves between them. Every electron that moves to the negative plate leaves a positive nucleus behind. As the plates charge, the potential difference between the places increases. The current through the circuit decreases until the capacitor becomes fully charged. C   Return to Table of Contents The plates have equal magnitudes of charges, but one is positive, the other negative. L What does the lamp look like while the capacitor is charging? Slide 102 () / 127 Slide 103 / 127 Capacitance Capacitance When a battery is connected to a capacitor, charge moves between them. Every electron that moves to the negative plate leaves a positive nucleus behind. As the While plates the capacitor charge, the is charging, potential its difference resistance between is increasing the places so the increases. current in the circuit is decreasing. The Therefore current through the lamp the gets circuit dimmer decreases until until the the capacitor current becomes stops and fully the charged. lamp goes out The plates have equal magnitudes of charges, but one is positive, the other negative. C   L If the battery is now disconnected and current is allowed to flow, the capacitor discharges. The current decreases until the capacitor is fully discharged. The potential difference decreases until the capacitor is discharged. What happens to the lamp? L C  What does the lamp look like while the capacitor is charging?
26 Slide 103 () / 127 Capacitance If the battery is now disconnected and current is allowed to flow, the capacitor discharges. Slide 104 / In which of the following circuits will the capacitor store charge if the battery is disconnected? Select two answers. A B The current decreases until the capacitor is fully discharged. As the capacitor decreases, the potential difference also decreases The potential difference causing decreases the lamp until to start out bright the capacitor is discharged. but get dimmer until the capacitor is fully discharged and the lamp goes out. What happens to the lamp? C  C D L Slide 104 () / 127 Slide 105 / In which of the following circuits will the capacitor store charge if the battery is disconnected? Select two answers. Equivalent Capacitance A B Circuits can be redrawn as if there were only a single capacitor and battery. By reducing the circuit this way, the circuit becomes easier to study. C D B, C The process of reducing the resistors in a circuit is called finding the equivalent Capacitance for capacitors in series (C S) and parallel (C P). Slide 106 / 127 Slide 107 / 127 Parallel Circuits: Equivalent Capacitance Parallel Circuits: Equivalent Capacitance What is the voltage across each capacitor? C2 The voltage across each capacitor is the same. C2 C1 = 1 = 2 C1 What is the charge on each capacitor? The total charge is the sum of the charge on all the capacitors. Q = Q 1 Q 2
27 Slide 108 / 127 Parallel Circuits: Equivalent Capacitance Slide 109 / 127 Series Circuits: Equivalent Capacitance Since = 1 = 2, Q = Q 1 Q 2 and Q = C C = C 1 1 C 2 2 Replace 1 and 2 with. C2 C1 The sum of the voltage drops across each of the resistors in a series circuit equals the voltage of the battery. C1 C2 C = C 1 C 2 Divide both sides by. = 1 2 The charge on each capacitor is the same. C = C 1 C 2 Q = Q 1 = Q 2 So, for capacitors in parallel C P = ΣC i Slide 110 / 127 Slide 111 / 127 Series Circuits: Equivalent Capacitance Equivalent Capacitance Since = 1 2, Q = Q 1 = Q 2 and = Q/C C1 C2 Finding equivalent capacitance is like finding equivalent resistance, only reversed. Capacitors in series are added like resistors in parallel. Q/C = Q 1/C 1 Q 2/C 2 Replace Q 1 and Q 2 with Q. Q/C = Q/C 1 Q/C 2 Divide both sides by Q. Capacitors in parallel are added like resistors in series. 1/C = 1/C 1 1/C 2 So, for capacitors in series 1/C S = Σ1/C i Slide 112 / 127 Slide 112 () / What is the equivalent capacitance (in mf) if C 1 is 4mF and C 2 is 6mF? C2 C1
28 Slide 113 / 127 Slide 113 () / What is the equivalent capacitance (in mf) if C 1 is 4mF and C 2 is 6mF? 40 What is the equivalent capacitance (in mf) if C 1 is 4mF and C 2 is 6mF? C1 C2 C1 C2 Slide 114 / 127 Slide 114 () / What is the equivalent capacitance (in μf) if C 1 is 5μF and C 2 is 11μF? C2 C1 Slide 115 / 127 Slide 115 () / What is the equivalent capacitance (in nf) if C 1 is 9nF and C 2 is 3nF? 42 What is the equivalent capacitance (in nf) if C 1 is 9nF and C 2 is 3nF? C1 C2 C1 C2
29 Slide 116 / 127 Slide 117 / 127 RC Circuits RC Circuits A resistorcapacitor circuit is a circuit composed of resistors and capacitors that are connected to voltage source. Return to Table of Contents Slide 118 / 127 RC Circuits When the switch is open, there is no current in the top branch with the capacitor and this circuit is simply two light bulbs in series. The current through the battery current would be /2R. Slide 119 / 127 RC Circuits Immediately after the switch is closed, there is no resistance in the branch with the capacitor so all of the current goes through that branch and bypasses the second light bulb. Therefore the current through the battery increases and is /R. Slide 120 / 127 RC Circuits A long time after the switch is closed, the capacitor is fully charged and there is no more current in the top branch. The rest of the circuit behaves as if the capacitor was disconnected. Therefore the current through the battery is back to /2R. Slide 121 / Four identical light bulbs are connected in a circuit with a capacitor as shown. The switch is open. Rank the voltage from greatest to least. A 3 > 1 > 2 > 4 B 1 = 2 = 3 > C 4 > 3 > 1 = 2 D 4 = 3 > 1 = 2 4
30 Slide 121 () / 127 Slide 122 / Four identical light bulbs are connected in a circuit with a capacitor as shown. The switch is open. Rank the voltage from greatest to least. 44 Four identical light bulbs are connected in a circuit with a capacitor as shown. Immediately after the switch is closed, rank current from greatest to least. A 3 > 1 > 2 > A I 4 = I 3 > I 1 > I B 1 = 2 = 3 > 4 3 B I 1 = I 2 = I 4 > I 3 3 C 4 > 3 > 1 = 2 D 4 = 3 > 1 = 2 4 C C I 4 > I 3 > I 1 = I 2 D I 4 > I 3 = I 1 = I 2 4 Slide 122 () / 127 Slide 123 / Four identical light bulbs are connected in a circuit with a capacitor as shown. Immediately after the switch is closed, rank current from greatest to least. 45 Four identical light bulbs are connected in a circuit with a capacitor as shown. The switch has been closed for a long time. Rank the light bulbs in order of brightness. A I 4 = I 3 > I 1 > I A 4 > 3 > 1 = B I 1 = I 2 = I 4 > I 3 C I 4 > I 3 > I 1 = I 2 D I 4 > I 3 = I 1 = I D B 1 = 2 = 3 = 4 C 1 = 2 > 3 > 4 D 3 = 4 > 1 = Slide 123 () / 127 Slide 124 / Four identical light bulbs are connected in a circuit with a capacitor as shown. The switch has been closed for a long time. Rank the light bulbs in order of brightness. Energy Stored in RC Circuits Remember from the previous chapter that capacitors can store potential energy. A 4 > 3 > 1 = 2 B 1 = 2 = 3 = 4 C 1 = 2 > 3 > 4 D 3 = 4 > 1 = A 3 The energy stored in a capacitor is given by: Using, we can also substitute for Q and and get the following: and
31 Slide 125 / 127 Slide 125 () / A 3 mf capacitor is connected to a resistor with a resistance of 2Ω and battery with a potential difference of 6. How much energy, in Joules, is stored in the capacitor? 46 A 3 mf capacitor is connected to a resistor with a resistance of 2Ω and battery with a potential difference of 6. How much energy, in Joules, is stored in the capacitor? 2Ω 3mF 2Ω 3mF 6 6 Slide 126 / 127 Slide 126 () / Now another resistor with a resistance of 1 Ω and a switch are connected to the capacitor in parallel. How much energy, in Joules, is stored in the capacitor? 47 Now another resistor with a resistance of 1 Ω and a switch are connected to the capacitor in parallel. How much energy, in Joules, is stored in the capacitor? 1Ω 1Ω 2Ω 3mF 2Ω Since the switch is open it is the same 3mFas it was without the resistor. 6 6 Slide 127 / 127 Slide 127 () / Now the switch has been closed for a long time. How much energy, in Joules, is stored in the capacitor? 48 Now the switch has been closed for a long time. How much energy, in Joules, is stored in the capacitor? 1Ω 1Ω 2Ω 3mF 2Ω 3mF 6 6
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 informationCircuits. 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 informationElectric 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 informationAlgebra Based Physics
Page 1 of 105 Algebra Based Physics Electric Current & DC Circuits 20151006 www.njctl.org Page 2 of 105 Electric Current & DC Circuits Circuits Conductors Resistivity and Resistance Circuit Diagrams
More informationCircuits. Electric Current & DC Circuits Circuits. Unit 6. April Electric Current. Electric Current. Electric Current. ΔQ Δt
Electric Current & DC Circuits Electric Current & DC Circuits Circuits Conductors esistivity and esistance Click on the topic to go to that section Circuit Diagrams Measurement Electric Current Circuits
More informationAP Physics C. Electric Circuits III.C
AP Physics C Electric Circuits III.C III.C.1 Current, Resistance and Power The direction of conventional current Suppose the crosssectional area of the conductor changes. If a conductor has no current,
More informationAP Physics C  E & M
AP Physics C  E & M Current and Circuits 20170712 www.njctl.org Electric Current Resistance and Resistivity Electromotive Force (EMF) Energy and Power Resistors in Series and in Parallel Kirchoff's
More informationAP Physics C  E & M
Slide 1 / 27 Slide 2 / 27 AP Physics C  E & M Current, Resistance & Electromotive Force 20151205 www.njctl.org Slide 3 / 27 Electric Current Electric Current is defined as the movement of charge from
More informationIn 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 informationAC vs. DC Circuits. Constant voltage circuits. The voltage from an outlet is alternating voltage
Circuits AC vs. DC Circuits Constant voltage circuits Typically referred to as direct current or DC Computers, logic circuits, and battery operated devices are examples of DC circuits The voltage from
More information52 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 informationELECTRICITY & 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 informationElectric 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
More informationMasteringPhysics: Assignment Print View. Problem 30.50
Page 1 of 15 Assignment Display Mode: View Printable Answers phy260s08 homework 13 Due at 11:00pm on Wednesday, May 14, 2008 View Grading Details Problem 3050 Description: A 15cmlong nichrome wire is
More informationCapacitance. A different kind of capacitor: Work must be done to charge a capacitor. Capacitors in circuits. Capacitor connected to a battery
Capacitance The ratio C = Q/V is a conductor s self capacitance Units of capacitance: Coulomb/Volt = Farad A capacitor is made of two conductors with equal but opposite charge Capacitance depends on shape
More informationLecture Outline Chapter 21. Physics, 4 th Edition James S. Walker. Copyright 2010 Pearson Education, Inc.
Lecture Outline Chapter 21 Physics, 4 th Edition James S. Walker Chapter 21 Electric Current and Direct Current Circuits Units of Chapter 21 Electric Current Resistance and Ohm s Law Energy and Power
More information1. How does a light bulb work?
AP Physics 1 Lesson 12.a Electric Current and Circuits Outcomes 1. Determine the resistance of a resistor given length, crosssectional area and length. 2. Relate the movement of charge to differences
More informationTactics Box 23.1 Using Kirchhoff's Loop Law
PH203 Chapter 23 solutions Tactics Box 231 Using Kirchhoff's Loop Law Description: Knight/Jones/Field Tactics Box 231 Using Kirchhoff s loop law is illustrated Learning Goal: To practice Tactics Box 231
More informationUnit 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 informationPhysics 115. General Physics II. Session 24 Circuits Series and parallel R Meters Kirchoff s Rules
Physics 115 General Physics II Session 24 Circuits Series and parallel R Meters Kirchoff s Rules R. J. Wilkes Email: phy115a@u.washington.edu Home page: http://courses.washington.edu/phy115a/ 5/15/14 Phys
More informationELECTRIC CURRENT. Ions CHAPTER Electrons. ELECTRIC CURRENT and DIRECTCURRENT CIRCUITS
LCTRC CURRNT CHAPTR 25 LCTRC CURRNT and DRCTCURRNT CRCUTS Current as the motion of charges The Ampère Resistance and Ohm s Law Ohmic and nonohmic materials lectrical energy and power ons lectrons nside
More informationScience Olympiad Circuit Lab
Science Olympiad Circuit Lab Key Concepts Circuit Lab Overview Circuit Elements & Tools Basic Relationships (I, V, R, P) Resistor Network Configurations (Series & Parallel) Kirchhoff s Laws Examples Glossary
More informationElectricity 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 informationElectric 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 informationElectric 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 informationElectricity Mock Exam
Name: Class: _ Date: _ ID: A Electricity Mock Exam Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.. What happens when a rubber rod is rubbed
More informationChapter 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 informationElectron 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 informationDirect Current (DC) Circuits
Direct Current (DC) Circuits NOTE: There are short answer analysis questions in the Participation section the informal lab report. emember to include these answers in your lab notebook as they will be
More informationCLASS 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 informationChapter 16. Current and Drift Speed. Electric Current, cont. Current and Drift Speed, cont. Current and Drift Speed, final
Chapter 6 Current, esistance, and Direct Current Circuits Electric Current Whenever electric charges of like signs move, an electric current is said to exist The current is the rate at which the charge
More informationElectric 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 informationMagnets 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
More informationChapter 20 Electric Circuits
Chapter 0 Electric Circuits Chevy olt  Electric vehicle of the future Goals for Chapter 9 To understand the concept of current. To study resistance and Ohm s Law. To observe examples of electromotive
More informationElectricity. 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 information3/17/2009 PHYS202 SPRING Lecture notes Electric Circuits
PHYS202 SPRING 2009 Lecture notes Electric Circuits 1 Batteries A battery is a device that provides a potential difference to two terminals. Different metals in an electrolyte will create a potential difference,
More informationA 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 informationChapter 7 DirectCurrent Circuits
Chapter 7 DirectCurrent Circuits 7. Introduction... 7. Electromotive Force... 7.3 Resistors in Series and in Parallel... 4 7.4 Kirchhoff s Circuit Rules... 6 7.5 VoltageCurrent Measurements... 8 7.6
More information10/14/2018. Current. Current. QuickCheck 30.3
Current If QCurrent is the total amount of charge that has moved past a point in a wire, we define the current I in the wire to be the rate of charge flow: The SI unit for current is the coulomb per second,
More informationLABORATORY 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 informationChapter 28. Direct Current Circuits
Chapter 28 Direct Current Circuits Circuit Analysis Simple electric circuits may contain batteries, resistors, and capacitors in various combinations. For some circuits, analysis may consist of combining
More informationChapter 21 Electric Current and Direct Current Circuits
Chapter 21 Electric Current and Direct Current Circuits 1 Overview of Chapter 21 Electric Current and Resistance Energy and Power in Electric Circuits Resistors in Series and Parallel Kirchhoff s Rules
More informationClosed 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 informationChapter 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 informationChapter 27. Circuits
Chapter 27 Circuits 1 1. Pumping Chagres We need to establish a potential difference between the ends of a device to make charge carriers follow through the device. To generate a steady flow of charges,
More informationElectric Currents and Simple Circuits
1 Electric Currents and Simple Circuits Electrons can flow along inside a metal wire if there is an Efield present to push them along ( F= qe). The flow of electrons in a wire is similar to the flow
More informationElectricity
Electricity Electric Charge There are two fundamental charges in the universe. Positive (proton) has a charge of +1.60 x 1019 C Negative (electron) has a charge of 1.60 x 1019 C There is one general
More informationReview. 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 informationPH 102 Exam I N N N N. 3. Which of the following is true for the electric force and not true for the gravitational force?
Name Date INSTRUCTIONS PH 102 Exam I 1. nswer all questions below. ll problems have equal weight. 2. Clearly mark the answer you choose by filling in the adjacent circle. 3. There will be no partial credit
More informationPhysics 1302W.400 Lecture 21 Introductory Physics for Scientists and Engineering II
Physics 1302W.400 Lecture 21 Introductory Physics for Scientists and Engineering II In today s lecture, we will learn to: Calculate the resistance of a conductor depending on the material and shape Apply
More informationPH 2222C Fall Circuits. Lectures Chapter 27 (Halliday/Resnick/Walker, Fundamentals of Physics 8 th edition)
PH 2222C Fall 2012 Circuits Lectures 1112 Chapter 27 (Halliday/Resnick/Walker, Fundamentals of Physics 8 th edition) 1 Chapter 27 Circuits In this chapter we will cover the following topics: Electromotive
More informationElectric Current. Volta
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
More informationPhysics 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 informationFlow Rate is the NET amount of water passing through a surface per unit time
Electric Current An Analogy Water Flow in a Pipe H 2 0 gallons/minute Flow Rate is the NET amount of water passing through a surface per unit time Individual molecules are bouncing around with speeds of
More informationCan You Light the Bulb?
AP PHYSCS 2 Can You Light the Bulb? UNT 4 DC circuits and RC circuits. CHAPTER 16 DC CRCUTS 1. Draw wires and make the bulb light. 2. Modify your drawing and use ONE wire only! Complete circuits To check
More informationDirect Current Circuits. February 18, 2014 Physics for Scientists & Engineers 2, Chapter 26 1
Direct Current Circuits February 18, 2014 Physics for Scientists & Engineers 2, Chapter 26 1 Kirchhoff s Junction Rule! The sum of the currents entering a junction must equal the sum of the currents leaving
More informationLESSON 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 informationBasic 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
More informationElectric Currents. Resistors (Chapters 2728)
Electric Currents. Resistors (Chapters 2728) Electric current I Resistance R and resistors Relation between current and resistance: Ohm s Law Resistivity ρ Energy dissipated by current. Electric power
More informationCHAPTER 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 informationClass 8. Resistivity and Resistance Circuits. Physics 106. Winter Press CTRLL to view as a slide show. Class 8. Physics 106.
and Circuits and Winter 2018 Press CTRLL to view as a slide show. Last time we learned about Capacitance Problems ParallelPlate Capacitors Capacitors in Circuits Current Ohm s Law and Today we will learn
More informationResistivity 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 00.006 Copper.6 x 00.006 Aluminum.65 x 00.0049 Tungsten
More information12/2/2018. Monday 12/17. Electric Charge and Electric Field
Electricity Test Monday 1/17 Electric Charge and Electric Field 1 In nature, atoms are normally found with equal numbers of protons and electrons, so they are electrically neutral. By adding or removing
More informationRECALL?? 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 informationCollege Physics B  PHY2054C
Power College  PHY2054C and 09/15/2014 My Office Hours: Tuesday 10:00 AM  Noon 206 Keen Building PHY2054C Power First MiniExam this week on Wednesday!! Location: UPL 101, 10:1011:00 AM Exam on chapters
More informationPhysics 142 Steady Currents Page 1. Steady Currents
Physics 142 Steady Currents Page 1 Steady Currents If at first you don t succeed, try, try again. Then quit. No sense being a damn fool about it. W.C. Fields Electric current: the slow average drift of
More informationCoulomb s constant k = 9x10 9 N m 2 /C 2
1 Part 2: Electric Potential 2.1: Potential (Voltage) & Potential Energy q 2 Potential Energy of Point Charges Symbol U mks units [Joules = J] q 1 r Two point charges share an electric potential energy
More informationCHARGE 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 informationElectricity and Magnetism Module 4 Student Guide
Electricity and Magnetism Module 4 Student Guide Note: each time you are finished with a circuit we ask that you disconnect all wires, so that the next circuit you investigate starts with a blank slate.
More informationNORTHERN ILLINOIS UNIVERSITY PHYSICS DEPARTMENT. Physics 211 E&M and Quantum Physics Spring Lab #4: Electronic Circuits I
NORTHERN ILLINOIS UNIVERSITY PHYSICS DEPARTMENT Physics 211 E&M and Quantum Physics Spring 2018 Lab #4: Electronic Circuits I Lab Writeup Due: Mon/Wed/Thu/Fri, Feb. 12/14/15/16, 2018 Background The concepts
More informationGr. 11 Physics Electricity
Gr. 11 Physics Electricity This chart contains a complete list of the lessons and homework for Gr. 11 Physics. Please complete all the worksheets and problems listed under Homework before the next class.
More informationPhysics 6B Summer 2007 Final
Physics 6B Summer 2007 Final Question 1 An electron passes through two rectangular regions that contain uniform magnetic fields, B 1 and B 2. The field B 1 is stronger than the field B 2. Each field fills
More informationConcepTest PowerPoints
ConcepTest PowerPoints Chapter 16 Physics: Principles with Applications, 7 th edition Giancoli 2014 Pearson Education, Inc. This work is protected by United States copyright laws and is provided solely
More informationVersion 001 CIRCUITS holland (1290) 1
Version CIRCUITS holland (9) This printout should have questions Multiplechoice questions may continue on the next column or page find all choices before answering AP M 99 MC points The power dissipated
More information16.1 Electrical Current
16.1 Electrical Current Electric Current Electric Current When the ends of an electric conductor are at different electric potentials, charge flows from one end to the other Flow of Charge Charge flows
More informationTopic 5.2 Heating Effect of Electric Currents
Topic 5.2 Heating Effect of Electric Currents Kari Eloranta 2017 Jyväskylän Lyseon lukio International Baccalaureate February 14, 2017 Topic 5.2 Heating Effect of Electric Currents In subtopic 5.2 we study
More informationPhysics 7B1 (A/B) Professor Cebra. Winter 2010 Lecture 2. Simple Circuits. Slide 1 of 20
Physics 7B1 (A/B) Professor Cebra Winter 2010 Lecture 2 Simple Circuits Slide 1 of 20 Conservation of Energy Density In the First lecture, we started with energy conservation. We divided by volume (making
More information5. ELECTRIC CURRENTS
5. ELECTRIC CURRENTS TOPIC OUTLINE Section Recommended Time Giancoli Section 5.1 Potential Difference, Current, Resistance 5.2 Electric Circuits 3h 19.1, 19.2 6.2 Electric Field and Force 6.3 Magnetic
More informationPhysics 212 Midterm 2 Form A
1. A wire contains a steady current of 2 A. The charge that passes a cross section in 2 s is: A. 3.2 1019 C B. 6.4 1019 C C. 1 C D. 2 C E. 4 C 2. In a Physics 212 lab, Jane measures the current versus
More informationInsulators Nonmetals 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 nonohmic conductors Series and parallel connection Energy in an electric circuit Xplanation 1. CONDUCTORS AND INSULATORS
More informationR R V I R. Conventional Current. Ohms Law V = IR
DC Circuits opics EMF and erminal oltage esistors in Series and in Parallel Kirchhoff s ules EMFs in Series and in Parallel Capacitors in Series and in Parallel Ammeters and oltmeters Conventional Current
More informationLab 10: DC RC circuits
Name: Lab 10: DC RC circuits Group Members: Date: TA s Name: Objectives: 1. To understand current and voltage characteristics of a DC RC circuit 2. To understand the effect of the RC time constant Apparatus:
More informationUNIT II CURRENT ELECTRICITY
UNIT II CUENT ELECTICITY Weightage : 07 Marks Electric current; flow of electric charges in a metllic conductor, drift velocity, mobility and their relation with electric current. Ohm s law electrical
More information9. 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
More informationEE301 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 informationName: 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 informationQuestion 3: How is the electric potential difference between the two points defined? State its S.I. unit.
EXERCISE (8 A) Question : Define the term current and state its S.I unit. Solution : Current is defined as the rate of flow of charge. I = Q/t Its S.I. unit is Ampere. Question 2: Define the term electric
More informationClicker Session Currents, DC Circuits
Clicker Session Currents, DC Circuits Wires A wire of resistance R is stretched uniformly (keeping its volume constant) until it is twice its original length. What happens to the resistance? 1) it decreases
More informationConcepTest PowerPoints
ConcepTest PowerPoints Chapter 19 Physics: Principles with Applications, 6 th edition Giancoli 2005 Pearson Prentice Hall This work is protected by United States copyright laws and is provided solely for
More informationChapter 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 informationDirect 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 informationDC Circuits. Electromotive Force Resistor Circuits. Kirchoff s Rules. RC Circuits. Connections in parallel and series. Complex circuits made easy
DC Circuits Electromotive Force esistor Circuits Connections in parallel and series Kirchoff s ules Complex circuits made easy C Circuits Charging and discharging Electromotive Force (EMF) EMF, E, is the
More informationElectron 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
More informationELECTRIC 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 informationPhysics 1214 Chapter 19: Current, Resistance, and DirectCurrent Circuits
Physics 1214 Chapter 19: Current, Resistance, and DirectCurrent Circuits 1 Current current: (also called electric current) is an motion of charge from one region of a conductor to another. Current When
More informationChapter 19 Lecture Notes
Chapter 19 Lecture Notes Physics 2424  Strauss Formulas: R S = R 1 + R 2 +... C P = C 1 + C 2 +... 1/R P = 1/R 1 + 1/R 2 +... 1/C S = 1/C 1 + 1/C 2 +... q = q 0 [1e t/(rc) ] q = q 0 e t/(rc τ = RC
More informationCurrent and Resistance
PHYS102 Previous Exam Problems CHAPTER 26 Current and Resistance Charge, current, and current density Ohm s law Resistance Power Resistance & temperature 1. A current of 0.300 A is passed through a lamp
More informationMaterials Needed 1 DCell battery 6 6inch pieces of wire 3 flashlight light bulbs 3 light bulb holders (optional)
Experiment Module 3 Electric Circuits Objective/Introduction This experiment explores building simple circuits and testing Ohm s Law. Students will start lighting a simple light bulb. Then they will explore
More informationElectricity & Magnetism
Electricity & Magnetism D.C. Circuits Marline Kurishingal Note : This chapter includes only D.C. In AS syllabus A.C is not included. Recap... Electrical Circuit Symbols : Draw and interpret circuit diagrams
More informationPhysics 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... and... at high voltage on its dome. dome 2. You
More information