1. APHY201 12/5/2015 1 20.6 Force between Two Parallel Wires   Wire #1 has a magnetic field that produces a force on wire #2

2. APHY201 12/5/2015 2 20.7 Solenoids and Electromagnets   The magnetic field of the coil can be increased by adding an iron core.

3. APHY201 12/5/2015 3 20.9 Torque on a Current Loop Torque = (Force)(Lever Arm) = NIAB sinθ

4. APHY201 12/5/2015 4 20.10 Applications

5. APHY201 12/5/2015 5 20.11 Mass Spectrometer   Determine a particle’s mass   Discovery of isotopes

6. APHY201 12/5/2015 6 20.12 Ferromagnetism   Magnetic domains: groups of aligned atoms What do they look like?   The motion of electrons in atoms: orbiting and “spinning” Most objects are non-magnetic since the electron motions are cancelled out by other electrons   Magnetic permeability B = B o + B M

7. APHY201 12/5/2015 7 Determine the direction of the force on a positive charge.

8. APHY201 12/5/2015 8 Determine the direction of the velocity on a negative charge.