1. Electromagnetism
Created by Craig Smiley (Harrison HS, West Lafayette, IN)
Supported by grant PHY
from the National Science Foundation
and by Purdue University

2. Magnetic Field Lab & Rubbing Nail Lab
Lesson 1 - Magnets
Magnetic Field Lab &
Rubbing Nail Lab

3. Magnetic Field Lines
Which is a correct diagram of the magnetic field lines in and around a bar magnet? A. B. C. D. N S N S N S N S

4. Permanent Magnets A magnet can attract what materials?
Any materials that have an electric charge
Any material that is a conductor
Any metal
Only materials that have ferromagnetic elements in it
Only other magnets

5. Permanent Magnets A magnet can repel what materials?
Any materials that have an electric charge
Any material that is a conductors
Any metal
Only materials that have ferromagnetic elements in it
Only other magnets

6. Lab Follow-up
An un-magnetized nail is brought near a magnet as illustrated. What pole with the head become?
North
South
Either
Neither

7. Lab Follow-up
What magnetic pole will the tip of the nail have after being rubbed with a magnet as illustrated?
North
South
Can’t be determined

8. Lab Follow-up
Which two ways will could you rub a nail with a magnet to make the pointed tip of the nail the North pole? A) 1 & 2 B) 1 & 3 C) 1 & 4 D) 2 & 3 E) 2 & 4

9. Permanent Magnet What would happen if you cut a bar magnet in half?
A. B. C.
D. The magnet would be broken making it two totally unmagnetized pieces of metal.
E. None of these

10. Permanent Magnets
What would a cause a magnet to be stronger than another magnet?
It could be bigger, thus increasing the total number of domains
It could have a higher percentage of domains pointing the same direction
It could have more densely packed domains, thus increasing the number of domains
Two of these
All of these

11. Permanent Magnets What would cause a magnet to become demagnetized?
Cut it in two
Heat it
Beat it against something
Two of these (A, B, C)
You can’t demagnetize a magnet

12. Geomagnetism
If we had a magnet that was able to spin freely (as though floating in a tub of water), which geographic direction would the south pole of the magnet point?
A) North
B) South
C) Can’t be determined

13. Lesson 2
Magnetic Field

14. Magnetic Field from a Wire
What is the direction of the magnetic field created by the current flowing down through this wire? A. B. C. D. E. F.

15. Magnetic Field from a Wire
What is the direction of the magnetic field created by the current flowing down through this wire? A. B. C. D.

16. Magnetic Field created by loop of wire
What is the direction of the magnetic field at point P inside the loop of wire that is created by current flowing through it in the direction illustrated? A. ⃝ B. ⃝ C. D. E. None of these P

17. Magnetic Field created by loop of wire
Which produces a stronger magnetic field at point P, if the current is the same and radius of the loop (R) is the same as the distance away from the wire (r)?
Loop
Straight wire
The same
Can’t be determined P

18. Magnetic Field created by a loop of wire
You are looking a wire loop from above. Which way is the current flowing through the wire loop to create this magnetic field?
To the right
To the left
Either to the right or the left; it doesn’t matter
None of these
I don’t know

19. Solenoid of Wire with Current
If an iron bar was placed inside of this solenoid, which side would be the North pole
Right
Left
Can’t be determined
Both
Neither

20. Magnetic Field in a Solenoid
What is the direction of the magnetic field created by current flowing this solenoid? A. B. C. D.

21. Electromagnet
Which way would the current need to be flowing in order to make the top end of the iron bar the North pole of the electromagnet?
top wire
 bottom wire
 top wire
 bottom wire
C. Can’t be determined
D. Don’t know

22. Electromagnet N S
Which way would the current need to be flowing in order to make this electromagnet repel this permanent magnet?
A. top wire
 bottom wire
 top wire
 bottom wire
C. Can’t be determined
D. Don’t know

23. Magnetic Force on moving charged particles
Lesson 3
Magnetic Force on moving charged particles

24. Examples using RHR #2

25. A proton is at rest at point P
A proton is at rest at point P. The direction of the magnetic force on the proton is best represented by: A. B. C. D.
E. None of these
Choice One
Choice Two
Choice Three
Choice Four
Choice Five
Choice Six P

26. Examples using RHR #2 A. B. C. D. E. F.
G. None
H. Can’t be determined

27. Examples using RHR #2 A. B. C. D. E. F.
G. None
H. Can’t be determined

28. Example Problem
A particle with a charge of -33μC moves at 2,000 m/s at 40⁰ through a 6.5 T magnetic field. What is the direction of the magnetic force on the charged particle? A B C D E F
G. None
H. Can’t be determined

29. Electric Motor
How will this loop of wire move if there is a current that flows around the loop as illustrated? A. B. C. D. E.
F. None of these

30. Electromagnetic Induction
Lesson 4
Electromagnetic Induction

31. Simple Model of a Generator
Which way will the current flow through the conductor as the conductor moves down?  
No current
Can’t be determined

32. Simple Model of a Generator
Which way will the current flow through the conductor as the conductor moves up along the metal bars?  
No current
Can’t be determined

33. Simple Model of a Generator
Which way will the magnetic force act on the electrons in the conductor as the conductor moves down along the metal bars?   ↑ ↓

34. Simple Model of a Generator
Which way will the magnetic force act on the conductor in the conductor as the conductor moves down along the metal bars?   ↑ ↓

35. Outlets
What kind of current comes out of outlets in the United States? AC DC
Both simultaneously
Depends on the appliance you plug in

36. Electric Company
What is coming from the electric company when we turn on a lamp in your bedroom?
Energy
Electrons
Both
Neither

37. Motor vs Generator
If you had an electric motor, could you use it to make a generator, by spinning it create electricity?
Yes
All the parts are there, but you would have to rearrange them differently before it could work.
No, that’s absurd
I don’t know

38. Electromagnetic Devices
Which device does a microphone function because of the same foundational fact? In other words, which device is the most similar in its functionality compared to a microphone?
Speaker
Generator
Motor
Two of these
All of these

39. Transformers

40. Transformers
Is it possible to cause current to flow in the secondary coil by turning the current in the primary coil on and off in this arrangement? (there is no physical connection between the two coils)
Yes No
Seems like a trick question, so yes

41. Transformers
When is a voltage induced in the secondary coil of wire when the primary coil is connected to a battery?
Right when the primary coil is turned on.
While the primary coil has a steady current flowing through it (when it is left on).
Right when the primary coil is turned off.
A & B
A & C

42. Transformer Why do transformers use alternating current?
Because that is the most common type of electricity…made from generators.
Because DC would get too hot.
Because the electrons don’t actually get transported, they just vibrate back and forth.
Because it creates a magnetic field in the coils that is constantly changing.
None of these

43. Transformer
What would happen if a transformer had a wooden core instead of an iron core?
It wouldn’t work…impossible
It would work, just not near as well
It would work just a well as an iron core
Depends on the type of wood

44. Transformer
Your cell phone runs off of a 6V battery. When you charge your phone at night, what is the black box you plug into the outlet?
Step-up transformer
Step-down transformer
Step-up and an Inverter (changes AC to DC)
Step-down and an Inverter (changes AC to DC)

45. Transformer What kind of transformer is this? Step-Up Step-Down Both
Neither
Can’t be determined

46. Transformer
In step-up transformer, what happens from the primary coil compared to the secondary coil?
Voltage increases, Power increases
Voltage increases, Power decreases
Voltage increases, Power remains the same
Voltage remains the same, Power increases
Voltage decreases, Power increases

47. Transformer
In step-up transformer, what happens to the current from the primary coil compared to the secondary coil?
Current increases
Current decreases
Current remains the same

48. Transformer
So in a step-up transformer the voltage in the secondary coil increases, and the current decreases. What must be true about the resistance of the secondary coil compared to the primary coil, based on Ohm’s Law (ΔV=IR)
Resistance must be more
Resistance must be less
Resistance must remain constant
Can’t be determined

49. Transformer
In step-down transformer, what happens from the primary coil compared to the secondary coil?
Voltage decreases, Current increases
Voltage decreases, Current decreases
Voltage decreases, Current remains the same
Voltage remains the same, Current decreases
Voltage increases, Current decreases

50. Transformer
Which would be the correct expression of ratios for the relationship between voltage (ΔV), number of loops (N), and current (I) from the primary1 and secondary2 coils?
A. ∆ 𝑉 1 ∆ 𝑉 2 = 𝑁 1 𝑁 2 = 𝐼 1 𝐼 2 B. ∆ 𝑉 1 ∆ 𝑉 2 = 𝑁 1 𝑁 2 = 𝐼 2 𝐼 1
C. ∆ 𝑉 1 ∆ 𝑉 2 = 𝑁 2 𝑁 1 = 𝐼 1 𝐼 2 D. ∆ 𝑉 1 ∆ 𝑉 2 = 𝑁 2 𝑁 1 = 𝐼 2 𝐼 1

51. Transformer
Which will dissipate less Power across power-lines, based off of this equation P=I2R?
High current
Low current
Which transformer causes this?
Step-up
Step-down