The Mass Spectrometer

2

21

/2

2

1 2

rx

q

mV

BqB

mvr

mqVv

qVmv

u93.2038

222

22

V

qxBm

q

mV

Brx

Isotope Separation Centrifuge and diffusion chamber

質譜儀

同位素分離

迴旋加速器 (cyclotrons)

迴旋頻率不因速率增加而改變，因此可用定頻交流電持續加速）

The resonance condition:When proton energy > 50Mev:

– Out of resonance (relativistic effect) – A huge magnet (4×106 m2) is needed for

high energy (500Gev) protons The proton sychrotron at Fermilab ca

n produces 1Tev proton

oscff

同步加速器 (synchrotrons)

Fermilab – 6.3km Tevatron

載流導線

載流導線所受的磁力

BLiF

iLBBqvF

viLitq

B

dB

d

sin

/

載流線圈

Speaker

Voice-coil positioner of a HDD

MHD Propulsion

Maglev Trains

EM Rail Gun

Magnetic Resonance Imaging

Magnetic Resonance Imaging

Positron Emission Tomography

Bone Scanning and Heart Disease

                               

             

Nuclear Medicine Images

III.3 電磁感應 Two symmetric Situations

– current loop + magnetic field → torque– torque + magnetic field → current

Two ExperimentsApplications

First Experiment

A Magnet is moving with respect to the loop

Second Experiment

The switch S is closed or opened

Faraday’s law

An emf is induced when the number of magnetic field lines that pass through the loop is changing

2m1T=1Wb =1Weber A dBB

turns)(N

dt

dN

dt

d

B

B

E

E

A Simple Example

RBlvi

BlvdtBldx

dtBlxddtd

BlxBAFvP

/

/

/)(/

,

RvLBRRBLvRiP

RvLBFvP

RvLBiLBF

/)/(

/

/

22222

222

22

Magnetic Tape Recording

Electric Guitar

The Playback Head

The moving-coil microphone

Transformer

Transmitting Electricity

Eddy currentsThe electromagnetic braking

The electromagnetic braking

Metal detector

III.4 電磁波

加速之電荷會產生電磁波 時變電場產生感應磁場；時變磁場產生感應電場

電磁波頻譜（光譜） 雷射（ Laser ）

LC 震盪器

時變電場與時變磁場

電波與磁波

) sin(

) sin(

t kx B B

t kx E E

m

m

電磁波頻譜

Theory of Lasers

He-Ne Lasers

Applications of Lasers

Compact Disc

Theory of X-ray

Medical X-rays

2D and 3D X-ray Images