CH 8: Magnetic Fields

8.5 – Applications of Electric and Magnetic Fields

Agenda Quiz

Lesson on Section on 8.5

Lots of Video’s

Story Time

Cyclotron Particle Accelerator http://

www.youtube.com/watch?v=cNnNM2ZqIsc

TRIUMF National laboratory in Vancouver has the largest cyclotron at 18m

Use of Magnetic Fields in Cyclotrons

Particles moving in a cyclotron are subjected to a uniform magnetic field which causes the particles to move in a circular path.Each time the charged particle enters a Dee it follows a semi-circular path and each time it traverses to the other Dee its speed is greater than before as it is subjected to an Electric field. Its energy has increased by W=qV.

Use of Magnetic Fields in Cyclotrons

The period of the charged particle is independent of its speed, this can be shown by the following,

Use of Magnetic Fields in Cyclotrons

The Kinetic Energy can be found by,

Use of Magnetic Fields in Cyclotrons

Example, A cyclotron is used to accelerate dueterons (q = 1.6 x 10-19C) of

mass 3.34 x 10-27 kg. The radius of the cyclotron is 30cm and the magnetic field applied to it has strength 1.6T. Find

(a)The period of the particles in their circular path.(b)The energy (in eV) of the particles leaving the cyclotron.

Use of Magnetic Fields in Cyclotrons

(a)The period of the particles in their circular path.

s

qBmT

8

19

27

102.8 6.1106.1

1034.32

2

Use of Magnetic Fields in Cyclotrons

(b) The energy (in eV) of the particles leaving the cyclotron.

MeVeV

J

mrBqK

52.5 1052.5

106.1108.83

eV into change1083.8

1034.32)3.0()6.1()106.1(

2

6

19

13-

13

27

22219

222

Life without Electricity http://www.youtube.com/watch?v=JzhGv

W5OH28

Motors and Generators http://www.youtube.com/watch?v=d_aT

C0iKO68

DC Motors http://www.youtube.com/watch?v=OncV

RVwbAOA

RFID Chips (Radio-Frequency Identification

Technology)

http://www.youtube.com/watch?v=MAA9JpGraoU

Technology that uses microchips that act as a transmitters and responders to communicate data by radio waves

Magneto-rheological Fluid (MR Fluid)

A fluid containing suspended iron particles that, when subjected to a magnetic field, changes to a solid

Changes state from solid to liquid and back using a magnetic field

MR Fluid Dampers http://

www.youtube.com/watch?v=SBXQ-6uI8GY

When in liquid form, can absorb shockwaves and reduce potential damage such as during Earthquakes

Used in:Shock absorbersWashing MachinesProstheticsExercise Equipment

High-Voltage Power Lines http://www.youtube.com/watch?v=9tzga

6qAaBA

MRI (Magnetic Resonance Imaging) http://

www.youtube.com/watch?v=H0adTNhzGxU

Hydrogen atoms in the body align themselves either in the direction of or opposite to the magnetic field

MRI device sends a regularly repeating radio frequency pulse, which causes the atoms to emit a regular energy signal which is detected by the scanner

Homeworkpg. 409 #10

• research the topic• answer the question in 250 words or less

(include 1-2 APA sources/references) • Hand in tomorrow