IB PHYSICS-Year1
(SECONDARY)
ESSENTIAL UNIT 10 (EU10)
ELECTRIC CURRENTS AND ELECTROMAGNETIC INDUCTION
(2011)
Unit Statement:
In this unit students are introduced to the principles that govern production, transmission, measuring of
and uses of electric current.
Understanding and harnessing of the power of flowing electric charge changed the quality of human
life arguably more than the harnessing of any other natural phenomena. Strangely, no one is in awe
anymore when witnessing all of the amazing things that happen when one turns on a switch.
SL students should not be required to complete TSWs 16-34. These are required for HL students only.
Essential Outcomes: (Must be Assessed)
1. TSW Define electric current
2. TSW Define resistance
𝜌𝐿
3. TSW Apply the equation for resistance in the form 𝑅 = 𝐴 , where ρ is the resistivity of the material
of the resistor.
4. TSW State Ohm’s law
5. TSW Compare ohmic and non-ohmic behavior
6. TSW Derive and apply expressions for electric power dissipation in resistors
7. TSW Solve problems involving potential difference, current and resistance
8. TSW Define electromotive force (emf)
9. TSW Describe the concept of internal resistance
10. TSW Apply the equations for resistors connected in series and parallel
11. TSW Draw circuit diagrams
12. TSW Describe the use of ideal ammeters and ideal voltmeters
13. TSW Describe a potential divider
14. TSW Explain the use of sensors in potential divider circuits
15. TSW Solve problems involving electric circuits
HL only
16. TSW Describe the inducing of an emf by relative motion between a conductor and a magnetic
field.
17. TSW Derive the formula for the emf induced in a straight conductor moving in a magnetic field.
18. TSW Define magnetic flux and magnetic flux linkage.
19. TSW Describe the production of an induced emf by a time-changing magnetic flux.
20. TSW State Faraday’s law and Lenz’s law
21. TSW Solve electromagnetic induction problems.
22. TSW Describe the emf induced in a coil rotating within a uniform magnetic field.
23. TSW Explain the operation of a basic alternating current (ac) generator.
24. TSW Describe the effect on the induced emf of changing the generator frequency.
25. TSW Discuss what is meant by the root mean squared (rms) value of an alternating current or
voltage.
26. TSW State the relation between peak and rms values for sinusoidal currents and voltages.
27. TSW Solve problems using peak and rms values.
28. TSW Solve ac circuit problems for ohmic resistors.
29. TSW Describe the operation of an ideal transformer and solve problems on the operation of
ideal transformers.
30. TSW Outline the reasons for power losses in transmission lines and real transformers.
31. TSW Explain the use of high-voltage step up and step-down transformers in the transmission of
electrical power.
32. TSW Solve problems on the operation of real transformers and power transmission.
33. TSW Suggest how extra-low-frequency electromagnetic fields, such as those created by electrical
appliances and power lines, induce currents within a human body.
34. TSW Discuss some of the possible risks involved in living and working near high-voltage power
lines.
Suggested Materials:
Textbook, Syllabus, Data Booklet, PSOW form, Physics Core Investigations
IB Question Bank CD; topic Electricity & Magnetism
LogerPro (Vernier software) and probes
Graphical Analysis software
Technology Resources:
PhET computer simulations: Ohm’s law, Battery voltage, Battery resistor circuit, Resistance in a wire,
Faraday’s electromagnetic lab, Circuit construction, etc.
http://phet.colorado.edu/en/simulations/category/new
Chris Hamper’s web page: http://www.rcnuwc.org/ibphysics/
Online Curriculum Center: http://occ.ibo.org/ibis/occ/guest/home.cfm
Destiny and Web Path Express (available through your library)
Suggested internal assessment for the unit:
4 hours of IA or more
Physics Core Investigations;
Investigation 14 - Ohm’s Law
Investigation 15 - Internal Resistance Of A Dry Cell
Investigation 16 - Heating Effect Of A Current
Investigation 18 - Voltage Divider Circuits
The suggested simulations are suitable for several interesting investigations.
What is the relationship between the number of loops and voltage generated?
What is the relationship between el. current and the strength of the generated electromagnet?
Suggested Instructional Strategies:
The students should be given examples of questions from previous IB exams.
Teachers should use questions and problems from the IB question bank.
Give students time to play with dry cells, resistors, light bulbs, magnets, volt and ampmeters….
Take your class on a field trip to a local power plant.
Discuss “the war of the currents” between T.A. Edison (DC) and Nicola Tesla (AC). What would the
world be like if DC had wan “the war?”
Challenge your students (and yourself) to go through one day without using any electricity at all.
Suggested assessment of mastery and beyond mastery of the unit:
It is strongly recommended that questions from past IB exams and from the IB question bank are used
for assessing mastery and beyond mastery.
Each TSW should be assessed with at least one question/problem. Some questions (for example
extended-response questions) can assess the mastery of more than one TSW.
B
To earn a B student will correctly answer
most questions that asses Lower Order
Thinking Skills (LOTS) and some questions
that assess Higher Order Thinking Skills
(HOTS).
SOME means at least a half
MOST means at least 70%
A
To earn an A student will correctly answer
most questions that asses Lower Order
Thinking Skills (LOTS) and most questions
that assess Higher Order Thinking Skills
(HOTS).
MOST mean at least 70%
For more detailed information on assessment of mastery and beyond mastery see the Suggested
Resources folder.