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Copyright © Texas Education Agency, 2013. All rights reserved. 1

Lesson Plan

Course Title Electronics

Session Title Ohm’s Law

Performance Objective Upon completion of this assignment, the student will be able to derive, explain, manipulate, and calculate resistance, voltage, and current of a given circuit using Ohm’s Law. The knowledge will be evidenced by correctly performing the procedures outlined in the assignment sheets and lab activities and by scoring an 85 % combined score on Ohm’s Law Exam One and Ohm’s Law Exam Two.

Specific Objectives

Identify the three components used in Ohm’s Law. Derive the equivalent expressions from Ohm’s Law. Derive equations from Ohm’s Law to define current, voltage, and resistance. Explain the relationship between resistance, current flow, and voltage drop in an

electric circuit. Calculate the current in a circuit, given resistance and applied voltage. Manipulate equations and solve problems using Ohm’s Law.

Preparation

TEKS Correlations This lesson, as published, correlates to the following TEKS. Any changes/alterations to the activities may result in elimination of any or all of the TEKS listed. Electronics

130.368 (c) o (5) The student implements the concepts and skills that form the technical

knowledge of electronics using project-based assessments. The student is expected to:

(A) apply Ohm's law, Kirchoff's laws, and power laws; and (C) demonstrate knowledge of the fundamentals of electronics theory.

Interdisciplinary Correlations Algebra I


111.39 (c) o (1) Mathematical process standards. The student uses mathematical

processes to acquire and demonstrate mathematical understanding. The student is expected to:

(A) apply mathematics to problems arising in everyday life, society, and the workplace; (B) use a problem-solving model that incorporates analyzing given information, formulating a plan or strategy, determining a solution, justifying the solution, and evaluating the problem-solving process and the reasonableness of the solution; (C) select tools, including real objects, manipulatives, paper and pencil, and technology as appropriate, and techniques, including mental math, estimation, and number sense as appropriate, to solve problems; (D) communicate mathematical ideas, reasoning, and their implications using multiple representations, including symbols, diagrams, graphs, and language as appropriate; (E) create and use representations to organize, record, and communicate mathematical ideas; (F) analyze mathematical relationships to connect and communicate mathematical ideas; and (G) display, explain, and justify mathematical ideas and arguments using precise mathematical language in written or oral communication.

111.39 (c) o (4) Linear functions, equations, and inequalities. The student applies the

mathematical process standards to formulate statistical relationships and evaluate their reasonableness based on real-world data. The student is expected to:

(A) calculate, using technology, the correlation coefficient between two quantitative variables and interpret this quantity as a measure of the strength of the linear association; (B) compare and contrast association and causation in real-world problems; and (C) write, with and without technology, linear functions that provide a reasonable fit to data to estimate solutions and make predictions for real-world problems.

111.39 (c) o (5) Linear functions, equations, and inequalities. The student applies the

mathematical process standards to solve, with and without technology, linear equations and evaluate the reasonableness of their solutions. The student is expected to:

(A) solve linear equations in one variable, including those for which the application of the distributive property is necessary and for which


variables are included on both sides. English Language Arts and Reading, English II

110.32 (b) o (24) Listening and Speaking/Listening. Students will use comprehension skills

to listen attentively to others in formal and informal settings. Students will continue to apply earlier standards with greater complexity. Students are expected to:

(A) listen responsively to a speaker by taking notes that summarize, synthesize, or highlight the speaker's ideas for critical reflection and by asking questions related to the content for clarification and elaboration; and (B) follow and give complex oral instructions to perform specific tasks, answer questions, solve problems, and complete processes.


Occupational Correlation (O*Net –www.onetonline.org) Job Title: Electrical and Electronics Repairers, Commercial and Industrial Equipment O*Net Number: 49-2094.00 Reported Job Titles: Control Technician, Electronics Technician, Industrial Electrician, Electrical Technician, Electrician, Electrical and Instrument Technician (E&I Tech), Instrument and Electrical Technician (I&E Tech), Electrical and Instrument Mechanic, Repair Technician, Service Technician Tasks

Test faulty equipment to diagnose malfunctions, using test equipment or software, and applying knowledge of the functional operation of electronic units and systems.

Inspect components of industrial equipment for accurate assembly and installation or for defects, such as loose connections or frayed wires.

Install repaired equipment in various settings, such as industrial or military establishments.

Examine work orders and converse with equipment operators to detect equipment problems and to ascertain whether mechanical or human errors contributed to the problems.

Perform scheduled preventive maintenance tasks, such as checking, cleaning, or repairing equipment, to detect and prevent problems.

Study blueprints, schematics, manuals, or other specifications to determine installation procedures.

Set up and test industrial equipment to ensure that it functions properly. Repair or adjust equipment, machines, or defective components, replacing worn

parts, such as gaskets or seals in watertight electrical equipment. Maintain equipment logs that record performance problems, repairs,

calibrations, or tests. Calibrate testing instruments and installed or repaired equipment to prescribed

specifications. Soft Skills

Repairing

Quality Control Analysis

Operation Monitoring

Troubleshooting

Critical Thinking

Equipment Maintenance

Active Listening

Equipment Selection

Complex Problem Solving Judgment and Decision Making


References

Buchla, D. and Floyd, T. (2005). The science of electronics: DC/AC. Chapter four. Upper Saddle River, NJ: Pearson Prentice Hall.

Floyd, T. (1993). Principles of electric circuits: Electron flow version. Don Mills, Ontario: Macmillian Publishing Co.

Robertson, L. (1980). Basic electronics I. Stillwater, OK: Mid-American Vocational Curriculum Consortium, Inc.

Instructional Aids

Ohm’s Law slide presentation and notes

Handout One- Terms and Definitions

Handout One Answer Key

Handout Two- The Ohm’s Law Circle; Table of Metric Prefixes

Handout Two Answer Key

Lab One- Use Ohm’s Law with Circuit Measurements

Activity One- Solve Problems for an Unknown Voltage

Activity Two- Solve Problems for an Unknown Amperage

Activity Three- Solve Problems for an Unknown Resistance

Activity Four- Solve Problems for an Unknown Variable

Activities One-Four Answer Keys

Ohm’s Law Exam One

Ohm’s Law Exam Two

Ohm’s Law Exam One and Two Answer Keys

Materials Needed

Pencil and paper

Calculator

Breadboards and leads

Power supplies

Multimeters

Equipment Needed

Computer and software

Projector and screen

Whiteboard

Learner Preparation


Read chapter on current in textbook

Complete lab activities

Watch slide presentation and take notes on materials

Introduction

Introduction (LSI Quadrant I)

Say o Electrons in a circuit behave in a certain manner that is predictable when

dealing with values of each component within the circuitry.

Ask o Would you be able to predict for certain the values of an unknown

component given the two other components and the law that governs that electron behavior?

Say o A law of nature has been determined by a man named Ohm, who when given

certain conditions and values could predict the unknown value. Thus allowing us to design any possibility that we would or could imagine. Tomorrow is here today. Let us explore and use the law, Ohm’s Law, to explain circuit design and our own abilities to deal with electricity.

Outline

Teachers can use the slide presentation, notes pages, and handouts in conjunction with the following outline.

Outline (LSI Quadrant II)

Teacher Notes

I. Introduction A. Overview B. Terms and definitions C. Units and the symbols

Slides 1-6 Begin Ohm’s Law slide presentation. Review the terms and definition and have students write them into their lab notebook. The next day, after you review these definitions, give students Handout One- Terms and Definitions and have them complete it.

II. Ohm’s Law Slide 7


A. Describe the mathematical relationship between current, voltage, and resistance.

B. Discovered by Georg Simon Ohm, a German physicist, in 1827.

C. Ohm spent most of his life as a high school teacher because his work was not well accepted by the scientific community.

D. The standard form should always be expressed as, “current equals voltage divided by resistance” because current is the result of those values.

III. The Ohm’s Law Circle A. Used as an aid to determine the different forms of Ohm’s Law. B. By the end of this lesson, students should know all of the forms of Ohm’s Law. C. Describe the use of the circle (cover the

unknown; the remaining two terms are the equation used to find the unknown). D. Slide 22 is a summary of the three forms of Ohm’s Law.

Slides 8-22 Go through the slides fairly quickly. Handout Two- The Ohm’s Law Circle; Table of Metric Prefixes can be given to students to learn to use Ohm’s Law, but it should not be used for any summative assessment.

IV. Visualize Ohm’s Law A. The current (amperes) in an electric circuit

equals the electromotive force or potential (volts) divided by the resistance (ohms).

B. E is an older, obsolete symbol for voltage that comes from the term electromotive force.

C. Use this slide to show the relationship between the units, volts, amps, and ohms.

Slide 23

V. Metric prefixes A. Use this slide and the table to review metric

prefixes. B. Resistance values are typically large and

expressed in kiloOhms or MegaOhms. C. Current values are typically small and expressed

in milliAmps or microAmps. D. Centi is included primarily because centimeter

is a common unit of length. Otherwise, this chart uses Engineering Notation.

Slide 24 This is included on Handout Two- The Ohm’s Law Circle; Table of Metric Prefixes for review purposes only, and it is not intended to be allowed for summative evaluation.


VI. Practice problems A. These problems illustrate the use of the Ohm’s

Law Circle to find the equation to solve for unknown values.

B. By the end of this lesson, (after working through the practice problems) students should know each of the three forms of Ohm’s Law.

C. Each of the three forms of Ohm’s Law is covered with an example.

D. Practice Problem One starts out with more detail, and the level of detail is reduced for successive problems.

E. Slide 44 shows a summary of the method the students should be using by the end of the lesson.

Slides 25-44 Try to be consistent about using the procedure to solve an equation with one unknown, using two known values. Hand out Activities One-Four to allow students to practice finding and using Ohm’s law.

VII. Practice problems using circuit schematics A. Have students use only the summary method

to solve for the unknowns. B. These slides give circuit information in the

form of circuit schematics. C. Review schematic symbols and their meaning.

Slides 45-47

VIII. Summary A. Given a circuit with known values, prove the

law correct.

Slide 48 Handout Lab One- Use Ohm’s Law with Circuit Measurements to use either for student practice or for teacher demonstration (depending on parts and supplies available).

IX. Administer Exams A. Ohm’s Law Exam One B. Ohm’s Law Exam Two

Grade exams using Ohm’s Law Exam One and Two Answer Keys. Students must receive 85 % combined score on the exams.

Application


Guided Practice (LSI Quadrant III)

The teacher will use materials listed in the lab activities to instruct how to read, measure with, and record data needed.

The students will observe, ask questions, and analyze the demonstration to be presented by the teacher.

Independent Practice (LSI Quadrant III)

The student will try to replicate the lab activities.

The student will answer the discussion questions on the Lab One- Use Ohm’s Law with Circuit Measurements handout.

The student will answer the questions in the four activity handouts and turn in for evaluation:

o Ohm’s Law Activity One- Solve Problems for an Unknown Voltage o Ohm’s Law Activity Two- Solve Problems for an Unknown Amperage o Ohm’s Law Activity Three- Solve Problems for an Unknown Resistance o Ohm’s Law Activity Four- Solve Problems for an Unknown Variable

Summary

Review (LSI Quadrants I and IV) Review the student’s data sheets to evaluate if individual or small group activity is the best approach for learning.

Evaluation

Informal Assessment (LSI Quadrant III)

The teacher will monitor each person or small group as they individually work to complete the assignments.

If re-teach is needed on any information or procedure, all those involved will stop and participate in the re-teach.

Formal Assessment (LSI Quadrant III, IV)

The student will be assessed by the accuracy of the completed assignments. Use the Activities One-Four Answer Keys to grade them.

The teacher will divide the final assessment into two parts. o Two formal exams: Exam One and Exam Two (written). Use the Exam One

Answer Key and the Exam Two Answer Key to grade them. o A measurement test of a series of exercises using the breadboards,

power supplies, and assorted loads or lamps to measure current, voltage, resistors, accurately.


Extension

Extension/Enrichment (LSI Quadrant IV)

The use of the multimeter to measure accurately current, voltage, and resistance becomes a vital part of the technical problem-solving skills needed in the world of work.

Thinking through a problem to arrive at the answer and the persistency to work past their frustrations tempers a student’s character.

There are points in the lab experience where the student takes some part in leadership skills; leading or following creates a sense of accomplishment that adds to the character of the involved students. Cognitive and leadership skills go hand in hand with solving life’s roadblocks.


Name: ____________________________________ Class: ________ Date ___/___/___

Terms and Definitions Handout One Define the following terms. 1. Voltage:

2. Current:

3. Resistance:

4. Electrical power:

5. Ohm’s Law:

6. Directly proportional:

7. Inversely proportional

Give the units and symbols for the following.

8. Voltage:

9. Current:

10. Resistance:

11. Electrical power:


Terms and Definitions Handout One Answer Key Define the following terms. 1. Voltage: electrical potential; an electrical pressure created by the buildup of

charge

2. Current: the flow or movement of electrons

3. Resistance: opposition to current flow

4. Electrical power: the rate of electrical energy used in a circuit

5. Ohm’s Law: a formula describing the mathematical relationship between voltage, current, and resistance

6. Directly proportional: having a constant ratio

7. Inversely proportional: having a constant but inverse ratio

Give the units and symbols for the following.

8. Voltage: volts, v

9. Current: amps, I

10. Resistance: Ohms, Ω

11. Electrical power: watts, P


Handout Two

The Ohm’s Law Circle

Table of Metric Prefixes


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Lab One- Use Ohm’s Law with Circuit Measurements

Equipment and materials_________________________________________________

Multimeter or ammeter and voltmeter with leads

DC Power Source

One 3.3-K ohm resistor and one 1-K ohm resistor

Switch, SPST

Procedure______________________________________________________________

1. Connect the DC power supply to one 3.3-K ohm resistor in series with an ammeter (Figure 1)

Figure 1 2. Turn on the power supply and adjust for a 3 volt output

3. Close the switch, then read and record the ammeter indication in the data table (Table 1)

OBSERVED COMPUTED __________ ___________

Data Table E I R E I R Step 3 3v ____ 3.3 KΩ ___ ___ ___ Step 5 6v ____ 3.3 KΩ ___ ___ ___ Step 9 3v ____ 4.3 KΩ ___ ___ ___ Step 12 ____ ____ 3.3 KΩ ___ ___ ___ Step 13 ____ ____ 3.3 KΩ ___ ___ ___ Step 14 ____ ____ 3.3 KΩ ___ ___ ___


Name: ____________________________________ Class: ________ Date ___/___/___ 4. Increase the output of the power supply to 6 volts

5. Read the ammeter indication and record on the data table

6. Compare the current observed in Step 3 with that observed in Step 5

NOTE: With no change in resistance, an increase in voltage results in (increase) (decrease) of circuit current

7. Turn off the power supply and install both resistors in series with the ammeter

(Figure 2)

Figure 2 8. Turn on the power supply and adjust for a 3 volt output

9. Read the ammeter indication and record in the data table

10. Compare the current observed in Step 9 with that observed in Step 3

NOTE: With no change in voltage, does an increase in resistance result in (increase) or (decrease) of circuit current?

11. Connect a voltmeter across the 3.3-K ohm resistor

12. Read the voltmeter indication and record on the data table

13. Observe the ammeter indication and adjust the power supply for a slight increase in the circuit current

14. Read the voltmeter indication and record on the data table

15. Compare the voltage observed in Step 12 with that observed in Step 14

NOTE: With no change in resistance, does an increase in current result in (increase) or (decrease) of voltage?

16. Use the observed values for E, I, and R and compare these values using Ohm’s Law

17. Record your results in the spaces provided in the data table


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law Activity One- Solve Problems for an Unknown Voltage

Directions State the appropriate formula, fill in variables, and answer with appropriate unit tag. Example Given current of 16 ma and resistance of 20 KΩ E=IR= (16ma) (20KΩ) = 320 v

Problems

Ohms Amps Volts 1. 6 20 _____ 2. 60 4 _____ 3. 2.5 9.6 _____ 4. 3 5 _____ 5. 0.16 75 _____ 6. 5 x 103 2 x 10-3 _____ 7. 10 x 103 1 x 10-6 _____ 8. 1M 8 µ _____ 9. 2K 2m _____ 10. 1 1 _____


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Two- Solve Problems for an Unknown Amperage


Problems

Volts Ohms Amps 1. 240 12 _____ 2. 110 11 _____ 3. 440 20 _____ 4. 120 30 _____ 5. 24 3 _____ 6. 5 x 10-6 1 _____ 7. 12 1 _____ 8. 2 x 10-3 4 x 10-3 _____ 9. 20 Kv 5 x 10+6 _____ 10. 1 Kv 0.5 x 106 _____


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Three- Solve Problems for an Unknown Resistance


Problems

Volts Amps Ohms 1. 240 4 _____ 2. 24 9.6 _____ 3. 12 5 _____ 4. 230 5 _____ 5. 24 8 _____ 6. 24 2ma _____ 7. 12 3µa _____ 8. 1 Kv 5 ma _____ 9. 1x 103 0.5x 10-3 _____ 10. 2.5x 103 5x 10-3 _____


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Four- Solve Problems for an Unknown Variable


Problems

1. 1600 Ω 25 ma _____ 2. 24v 9.6 Ω _____ 3. 63000 µa 34 Kv _____ 4. 6 KΩ 36 Kv _____ 5. 40 MΩ 8 µa _____ 6. 24 Kv 2 ma _____ 7. 12 MΩ 3µa _____ 8. 1 Kv 50 ma _____ 9. 1x 103 v 0.5x 10-3 a _____ 10. 2.5x 103 Ω 5x 10-3 a _____


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity One- Solve Problems for an Unknown Voltage Key


Problems

Ohms Amps Volts 1. 6 20 _120_

E = IR= 6 x 20 = 120 volts 2. 60 4 _240_

E = IR= 60 x 4 = 240 volts 3. 2.5 9.6 __24_

E = IR= 2.5 x 9.6 = 24 volts 4. 3 5 __15_

E = IR= 3 x 5 = 15 volts 5. 0.16 75 __12_

E = IR= 0.16 x 75 = 12 volts 6. 5 x 103 2 x 10-3 __10_

E = IR= 5000 x .002 = 10 volts 7. 10 x 103 1 x 10-6 _.001_

E = IR= 1000 x .000001 = .001 volts 8. 1M 8 µ ___8_

E = IR= 100000 x .000008 = 8 volts 9. 2K 2m ___4_

E = IR= 2000 x .002 = 4 volts 10. 1 1 ___1_

E = IR= 1 x 1 = 1 volts


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Two- Solve Problems for an Unknown Amperage Key


Problems

Volts Ohms Amps 1. 240 12 __20___

I = E/R = 240/ 12 = 20 amps 2. 110 11 __10___

I = E/R = 110/ 11 = 10 amps 3. 440 20 __20___

I = E/R = 440/ 20 = 20 amps 4. 120 30 ___4___

I = E/R = 120/ 30 = 4 amps 5. 24 3 ___8___

I = E/R = 24/ 3 = 8 amps 6. 5 x 10-6 1 .000005

I = E/R = .000005/ 1 = .000005 amps 7. 12 1 __12___

I = E/R = 12/ 1 = 12 amps 8. 2 x 10-3 4 x 10-3 __.5___

I = E/R = .002/ .004 = .5 amps 9. 20 Kv 5 x 10+6 _0.04__

I = E/R = 20000/ 500000 = 0.04 amps 10. 1 Kv 0.5 x 106 _0.02__

I = E/R = 1000/ 50000 = 0.02 amps


Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Three- Solve Problems for an Unknown Resistance Key


Problems

Volts Amps Ohms 1. 240 4 __60___

R= E/I = 240/ 4 = 60 Ω 2. 24 9.6 _2.5___

R= E/I = 24 / 9.6 = 2.5 Ω 3. 12 5 _2.4___

R= E/I = 12/ 5 = 2.4 Ω 4. 230 5 __46___

R= E/I = 230/ 5 = 46 Ω 5. 24 8 ___3___

R= E/I = 24/ 8 = 3 Ω 6. 24 2ma 12000__

R= E/I = 24/ .002 = 12000 Ω 7. 12 3µa 4000000

R= E/I = 12/ 0.000003 = 4000000 Ω 8. 1 Kv 5 ma 200000_

R= E/I = 1000/ 0.005 = 200000 Ω 9. 1x 103 0.5 x 10-3 2000000

R= E/I = 1000/ 0.0005 = 60 Ω 10. 2.5x 103 5 x 10-3 500000_

R= E/I = 2500/ 0.005 = 60 Ω

Copyright © Texas Education Agency, 2013. All rights reserved.

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Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Activity Four- Solve Problems for an Unknown Variable Key


Problems

1. 1600 Ω 25 ma 40 volts___ E = IR= 1600 x 0.025 = 40 volts

2. 24v 9.6 Ω 2.5 amps__

I = E/R = 24/ 9.6 = 2.5 amps 3. 63000 µa 34 Kv 539.68 Ω__

R= E/I = 34000/ 0.063 = 539.68 Ω 4. 6 KΩ 36 Kv 6 amps___

I = E/R = 36000/ 6000 = 6 amps 5. 40 MΩ 8 µa 320 volts__

E = IR= 0.000008 x 40000000 = 320 volts 6. 24 Kv 2 ma 12000000Ω

R= E/I = 24000/ 0.002 = 12000000 Ω 7. 12 MΩ 3µa 36 volts___

E = IR= 12000000 x .000003 = 36 volts 8. 1 Kv 50 ma 20000Ω___

R= E/I = 1000/ 0.05 = 20000 Ω 9. 1x 103 v 0.5x 10-3 a 2000000Ω_

R= E/I = 1000/ 0.0005 = 2000000Ω 10. 2.5x 103 Ω 5x 10-3 a 12.5 volts__

E = IR= 0.005 x 2500 = 1 volts


24

Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Exam One

Match the terms to the correct definitions. 1. Ampere A The unit of measurement of electrical current 2. Ohm B Unit of measure for the opposition to electron flow in a circuit 3. Volt C Unit of measure of potential difference 4. Watt D Unit of measure of power

Match the symbols or abbreviations with their correct definition.

5. R A Symbol for unit of measurement for power 6. E B Symbol for unit of measurement for electron flow 7. W C Symbol for unit of measurement for potential differences 8. I D Symbol for unit of measurement for opposition to electron flow

Solve the following problems.

9. Given that the total load for the circuit is 455Ω and the applied voltage is 40 volts, find the

current. A 11.375 ma B 1.1375 a C 87.912 ma D 879.12 µa

10. Given the following closed loop circuit condition, what is the total resistance in this circuit?

The current is 32.5 ma, the circuit of four loads different resistance values, and the applied voltage is 32.5 volts. A 1000Ω B 2 a C 32.5 v D 575 Ω


25

Name: ____________________________________ Class: ________ Date ___/___/___ 11. If the following loads have current of RT 24000Ω with an applied voltage of 25 volts, what is

the current to this circuit? A 1041.6 µa B 243 ma C 1.0416 ma D both a and c

12. Given the following variables, I= 125µa and the total resistance = 4MΩ, what is the voltage

applied? A 45 volts B 500 volts C 50 volts D 450 volts

13. Which symbol indicates 10-6?

A m B p C µ D K

14. Given the following values, applied voltage is 6 volts and the total resistance is 560 KΩ, find

the unknown variable. A 10.71 ma B 171.7 ma C 112 a D 11.2 ma

15. Solve for unknown voltage when I= 2 milliamps and R= 3 kilo-ohms. E= ____

A 66.67 volts B 1.5 volts C 6 volts D .667 volts

16. Solve for unknown current when E= 12 volts and R= 12 K ohms. I= _____ A 1.44 ma B 144 a C 1 ma D 24 ma


26

Name: ____________________________________ Class: ________ Date ___/___/___ 17. Solve for unknown resistance when E= 110 volts and I= 2 amperes. R= _____

A 50 Ω B 18.18 Ω C 220 Ω D 55 Ω

18. Solve for unknown voltage when I= 16 milliamps and R= 8 megaohms. E= ____

A 128 volts B 128 Kvolts C 200 volts D 24 volts

19. Solve for unknown current when E= 25 volts and R= 5 M ohms. I= _____

A 5 µa B 5 ma C 2 µa D 2 ma

20. Solve for unknown resistance when E= 22 volts and I= 2µa. R= _____

A 44 MΩ B 11 MΩ C 33 KΩ D 44 KΩ


The current is 325 µa, the circuit of four loads different resistance values, and the applied voltage is 120 volts. A 36923 Ω B 369.23 ma C 16918 Ω D 445 MΩ

22. Given the following values, applied voltage is 12 volts and the total resistance is 5.60 MΩ,

find the unknown variable. A 2.1 ma B 17.6 ma C 2.1µ a D 67.2 µa


27

Name: ____________________________________ Class: ________ Date ___/___/___ 23. Given the following values, current is 6 µa and the total resistance is 560 MΩ, find the

unknown variable. A 93.33 volts B 3360 volts C 336 volts D 33.6 volts


28

Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Exam One Key

Match the terms to the correct definitions. 1. Ampere A A The unit of measurement of electrical current

2. Ohm B B Unit of measure for the opposition to electron flow in a circuit

3. Volt C C Unit of measure of potential difference

4. Watt D D Unit of measure of power

Match the symbols or abbreviations with their correct definition.

5. R D A Symbol for unit of measurement for power

6. E C B Symbol for unit of measurement for electron flow

7. W A C Symbol for unit of measurement for potential differences

8. I B D Symbol for unit of measurement for opposition to electron flow

Solve the following problems.

9. Given that the total load for the circuit is 455Ω and the applied voltage is 40 volts, find the

current. A 11.375 ma B 1.1375 a C 87.912 ma D 879.12 µa

10. Given the following closed loop circuit condition, what is the total resistance in this circuit? The current is 32.5 ma, the circuit of four loads different resistance values, and the applied voltage is 32.5 volts. A 1000Ω B 2 a C 32.5 v D 575 Ω


29

Name: ____________________________________ Class: ________ Date ___/___/___

11. If the following loads have current of RT 24000Ω with an applied voltage of 25 volts, what is

the current to this circuit? A 1041.6 µa B 243 ma C 1.0416 ma D both A and C

12. Given the following variables, I = 125µa and the total resistance = 4MΩ, what is the voltage

applied? A 45 volts B 500 volts C 50 volts D 450 volts

13. Which symbol indicates 10-6?

A m B p C µ D K

14. Given the following values, applied voltage is 6 volts and the total resistance is 560 KΩ, find

the unknown variable. A 10.71 ma B 171.7 ma C 112 a D 11.2 ma

15. Solve for unknown voltage when I= 2 milliamps and R= 3 kilo-ohms. E= ____

A 66.67 volts B 1.5 volts C 6 volts D .667 volts

16. Solve for unknown current when E= 12volts and R= 12 K ohms. I= _____

A 1.44 ma B 144 a C 1 ma D 24 ma


30

Name: ____________________________________ Class: ________ Date ___/___/___ 17. Solve for unknown resistance when E= 110 volts and I= 2 amperes. R= _____

A 50 Ω B 18.18 Ω C 220 Ω D 55 Ω

18. Solve for unknown voltage when I=16 milliamps and R= 8 megaohms. E= ____

A 128 volts B 128 Kvolts C 200 volts D 24 volts

19. Solve for unknown current when E= 25 volts and R= 5 M ohms. I= _____

A 5 µa B 5 ma C 2 µa D 2 ma

20. Solve for unknown resistance when E= 22 volts and I= 2µa. R= _____

A 44 MΩ B 11 MΩ C 33 KΩ D 44 KΩ


The current is 325 µa, the circuit of four loads different resistance values, and the applied voltage is 120 volts. A 36923 Ω B 369.23 ma C 16918 Ω D 445 MΩ

22. Given the following values, applied voltage is 12 volts and the total resistance is 5.60 MΩ,

find the unknown variable. A 2.1 ma B 17.6 ma C 2.1µ a D 67.2 µa


31

Name: ____________________________________ Class: ________ Date ___/___/___ 23. Given the following values, current is 6 µa and the total resistance is 560 MΩ, find the

unknown variable. A 93.33 volts B 3360 volts C 336 volts D 33.6 volts


32

Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Exam Two

1. State Ohm’s Law. (5pts) 2. Draw the circular expression of Ohm’s Law. (4pts) 3. List three uses of Ohm’s Law in any order. (2pts each)

1. _________________________________________ 2. _________________________________________ 3. _________________________________________

The following problems are four points each: state formula (1), fill in values with labels (1), give the numeric answer (1), and provide the proper tag (1). Given Answer 4. 37 KΩ 10 µa __________

5. 2 ma 57 volts __________

6. 24 volts 250 KΩ __________

7. 100 µa 35 MΩ __________

8. 12.5 volts 13 µamps __________


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Name: ____________________________________ Class: ________ Date ___/___/___

Ohm's Law

Exam Two Key

1. State Ohm’s Law. (5pts) The current (amperes) in an electric circuit equals the electromotive force or potential differences (volts) divided by the resistance (ohms). 2. Draw the circular expression of Ohm’s Law. (4pts)

3. List three uses of Ohm’s Law. (2pts each) 1. __Used to calculate voltage ___E = IR_______ 2. __Used to calculate current ___I= E / R______ 3. __Used to calculate resistance _R= E / I______ (any order)

The following problems are four points each: state formula (1), fill in values with labels (1), give the numeric answer (1), and provide the proper tag (1). Given Answer 4. 37 KΩ 10 µa _0.37__volts

E = IR = .00001 a x 37000 Ω = 0.37 v_

5. 2 ma 57 volts 28500_ Ω__ R= E / I = 57 / .002 = 28500 Ω_______

6. 24 volts 250 KΩ _96_µamps I= E / R = 24 / 250000 = 96 µamps____

7. 100 µa 35 MΩ _3500 volts E = IR = .0001 x 35000000 = 3500 volts

8. 12.5 volts 13 µamps 9615385 Ω R= E / I = 125 / .000013 = 9615385 Ω_

model instruction plan - data.cteunt.orgdata.cteunt.org/.../7-06-ohms-law/07.06-ohms-law.pdf ·...

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