1. LARGEST SUPERCONDUCTING MAGNET ON EARTH!
ELECTROMAGNETISM

2. Hans Christian Oersted
In 1820 he discovered that a compass needle will move when placed next to current carrying wire.
This showed that electricity and magnetism are related.

3. Field around a current carrying wire.
Magnetic field lines are perpendicular, circular lines around the wire. They are vector quantities represented by (B).

4. First Right hand rule Thumb points in the direction of the current.
Fingers wrap around the wire in the direction of the magnetic field.
This field is in a counterclockwise direction.

5. Bending the wire into a loop will increase its magnetic field strength.

6. Solenoid- several loops wrapped into a coil to produce a magnetic field.
The combination of loops will produce polarity.

7. ELECTROMAGNETS
Connecting a coil of wire to a potential difference will make an electromagnet. To increase its strength you can:
a) Increase the current
b) Increase the number of loops
c) Place a metal bar in the coil

8. Second right hand rule: Used to identify poles of electromagnets
Fingers wrap around the coil in the direction of the current.
Thumb points to the magnetic north of the electromagnet. N S + I

9. Which end is the north pole?
S-pole I +
Which end is the north pole?
N-Pole

10. A magnetic field and an electric field at 90 degrees will produce a force .
Third right hand rule: used to determine the direction of the force.
First finger points in the direction of the magnetic field (B).
Thumb point in the direction of the current ( I ).
Middle finger points in the direction of the force on the wire (F).

11. All values are at 90 degrees.
Current ( I )
(B)
MagneticField
Force (F)

12. Drawing fields X X X X X X X X X X X X Two dimensional vectors
● ● ● ●
Field is out of the page
X X X X X X X X X X X X
Two dimensional vectors
Field is into the page

13. 3rd right hand rule What is the direction of the force on the wire?
Wire is forced upwards F I B N S I
What is the direction of the force on the wire?

14. Force, current and magnetic fields can be perpendicular to your paper
Force, current and magnetic fields can be perpendicular to your paper. X’s and dots can be used to indicate their direction.
The wire is perpendicular to the paper with the current traveling inward. The first right hand rule, shows the magnetic field is in a clockwise direction.

15. What is the direction of the force acting on the wire?
What is the direction of the magnetic field in the diagram? F
X X
X X B S N F ●
magnet
magnet I
*Current is outward

16. Homework:
Review book- pg
#1-16