MIDTERM-PT. 1

Question 1

WHAT ARE THE 3 PRINCIPAL TYPES OF MAGNETS:

Answer 1

1. NATURAL
2. PERMANENT
3. ELECTROMAGNETS

Question 2

MAGNET: EARTH

Answer 2

NATURAL

Question 3

MAGNET: ARTIFICIALLY PRODUCED

Answer 3

PERMANENT

Question 4

MAGNET: CONSIST OF WIRES

Answer 4

ELECTROMAGNETS

Question 5

WHAT ARE THE INTERACTION WITH MATTER: (3)

Answer 5

1. DIAMAGNETIC
2. FERROMAGNETIC
3. PARAMAGNETIC

Question 6

MATERIALS THAT ARE UNAFFECTED WHEN BROUGHT INTO A MAGNETIC FIELD

Answer 6

DIAMAGENETIC

Question 7

STRONGLY ATTRACTED BY A MAGNET; ALNICO

Answer 7

FERROMAGNETIC

Question 8

AN ALLOY OF ALUMINUM, NICKEL AND COBALT (MOST USEFUL MAGNETS PRODUCED BY FERRIMAGNETIC MATERIAL)

Answer 8

ALNICO

Question 9

MATERIALS THAT ARE BETWEEN THE CLASSIFICATION OF DIAMAGNETIC AND FERROMAGNETIC

Answer 9

PARAMAGENTIC

Question 10

SLIGHTLY ATTRACTED TO A MAGNET AND LOOSELY INFLUENCED BY AN EXTERNAL MAGNETIC FIELD

Answer 10

PARAMAGNETIC

Question 11

CONTRAST AGENTS USED IN MRI ARE _____

Answer 11

PARAMAGNETIC

Question 12

THE SI UNIT OF MAGNETIC FIELD STRENGTH

Answer 12

TESLA

Question 13

OLDER UNIT FOR MAGNETIC FIELD STRENGTH

Answer 13

GAUSS

Question 14

1 TESLA= ______ GAUSS

Answer 14

10,000

Question 15

THE EARTH’S MAGNETIC FIELD AT THE EQUATOR IS ____ uT

Answer 15

50

Question 16

the EARTH’S MAGNETIC FIELD AT THE POLES IS ____ uT

Answer 16

100

Question 17

LOWER TESLA = ___ QUALITY

Answer 17

LOWER

Question 18

TYPICALLY COILS OF WIRE THROUGH WHICH A MAGNETIC FIELD IS INDUCED

Answer 18

RESISTIVE MAGNETS

Question 19

ADVANTAGES: (MAGNET)
1. THEY ARE LIGHTER IN WEIGHT THAN PERMANENT MAGNETS
2. CAPITAL COSTS ARE LOW
3. DOES NOT REQUIRE CRYOGENS

Answer 19

RESISTIVE MAGNETS

Question 20

A LIQUID HELIUM INSULATOR; MAINTAINS NORMAL TEMPERATURE

Answer 20

CRYOGENS

Question 21

DISADVANTAGES: (MAGNET)
1. HIGH COSTS
2. LARGE QUANTITIES OF POWER REQUIRED TO MAINTAIN THE MAGNETIC
THE MAXIMUM FIELD STRENGTH IN A SYSTEM OF THIS TYPE IS LESS THAN 0.3T DUE TO ITS EXCESSIVE POWER REQUIREMENTS
3. SCAN TIMES ARE LONGER
4. RESISTIVE SYSTEM IS SAFE; CAN BE EASILY TURNED OFF INSTANTANEOUSLY
3. CREATE SIGNIFICANT STRAY FRINGE MAGNETIC FIELDS

Answer 21

RESISTIVE MAGNETS

Question 22

MAGNET: FIELD STRENGTH IS LESS THAN 0.3T

Answer 22

RESISTIVE MAGNETS

Question 23

THE MOST COMMONLY USED MAGNET

Answer 23

PERMANENT MAGNENT

Question 24

_____ IS USED TO MAKE PERMANENT MAGNETS

Answer 24

ALNICO ALLOY

Question 25

ADVANTAGES: (MAGNET) 1. THEY HAVE AN OPEN DESIGN; (CHILDREN, OBESE, AND CLAUSTROPHOBIC PATIENTS ARE SCANNED WITH EASE) 3. INTERVENTIONAL AND DYNAMIC PROCEDURES ARE POSSIBLE 4. THEY REQUIRE NO POWER SUPPLY 5. LOW IN OPERATING COSTS

Answer 25

PERMANENT MAGNETS

Question 26

DISADVANTAGES: (MAGNET) 1. THEY ARE EXCESSIVELY HEAVY 2. ONLY LOW FIXED FIELD STRENGTHS (0.2- 0.3 T) CAN BE ACHIEVED 3. LONGER SCAN TIMES ARE NEEDED, DUE TO LOWER FIELD STRENGTHS 4. COST OF THE MAGNET 5. HEAVY SUPPORTING STRUCTURES

Answer 26

PERMANENT MAGNETS

Question 27

MAGNET: FIELD STRENGTH IS 0.2- 0.3 T

Answer 27

PERMANENT MAGNET

Question 28

MAGNET: CONSIST OF COIL MADE OF NIOBIUM-TITANIUM (Nb-Ti) ALLOY

Answer 28

SUPERCONDUCTING MAGNETS

Question 29

ADVANTAGES: (MAGNET) 1. IT GIVES MAGNETIC FIELD STRENGTH (0.5-3T) WITH LOW POWER REQUIREMENTS 2. LOW OPERATING COSTS 3. RESISTANCE IS VIRTUALLY ELIMINATED, THERE IS NO LONGER A MECHANISM TO DISSIPATE CURRENT 4. NO ADDITIONAL POWER INPUT IS REQUIRED TO MAINTAIN THE HIGH MAGNETIC FIELD STRENGTH 5. ADVANCED APPLICATIONS ARE POSSIBLE AND OPTIMUM IMAGE QUALITY IS OBTAINED

Answer 29

SUPERCONDUCTING MAGNETS

Question 30

MAGNET: FIELD STRENGTH IS 0.5- 3T

Answer 30

SUPERCONDUCTING MAGNETS

Question 31

____ HAS A SPECIAL COOLING AGENT CALLED ____ ARE USE TO PRODUCE LOW TEMPERATURE (4K)

Answer 31

SUPERCONDUCTOR MAGNETS LIQUID CRYOGENS

Question 32

THE ELECTROMAGNETIC COILS ARE PLACED IN AN INSULATED CHAMBER CALLED ____ (CONTAINS HELIUM)

Answer 32

DEWAR/ CRYOSTAT

Question 33

THE PROCESS OF BRINGING THE SUPERCONDUCTING MAGNETS TO THE NECESSARY TEMPERATURE IS CALLED ____

Answer 33

RAMPING

Question 34

REFERS TO A MAGNET'S SUDDEN LOSS OF SUPERCONDUCTIVITY WITH SUBSEQUENT BREAKDOWN OF THE MAGNETIC FIELD; SUDDEN LOSS OF ABSOLUTE O TEMPERATURE

Answer 34

QUENCHING

Question 35

DEWAR: 2 TYPES OF CHAMBER

Answer 35

1. OUTER CHAMBER 2. INNER CHAMBER

Question 36

CONTAINS LIQUID NITROGEN

Answer 36

OUTER CHAMBER

Question 37

CONTAINS LIQUID HELIUM

Answer 37

INNER CHAMBER

Question 38

THIS RESULTS IN HELIUM ESCAPING FROM THE CRYOGEN BATH EXTREMELY RAPIDLY

Answer 38

QUENCHING

Question 39

63%; MAGNETIZATION

Answer 39

T1

Question 40

ANATOMY & SPIN (INTERACTION)

Answer 40

T2

Question 41

ARE BASED ON THE FACT THAT NUCLEI OF CERTAIN ELEMENTS HAVE A MAGNETIC MOMENT

Answer 41

MRI

Question 42

THE _____ IN MRI IS DUE TO THE ANGULAR MOMENT

Answer 42

PRECESSION

Question 43

ROTATION OF AN OBJECT AROUND THE DIRECTION OF A FORCE ACTING ON THAT OBJECT

Answer 43

PRECESSION

Question 44

USES THE SIGNAL FROM THE NUCLEI OF HYDROGEN ATOMS FOR IMAGE GENERATION

Answer 44

MRI

Question 45

PERTAINS TO ROTATION (CLOCKWISE/COUNTER CLOCKWISE)

Answer 45

ANGULAR MOMENT

Question 46

PERTAINS TO THE ALIGNMENT; PARALLEL/ ANTI-PARALLEL

Answer 46

MAGNETIC MOMENT

Question 47

NORMALLY PROTONS ARE ALIGNED IN RANDOM FASHION ALIGNMENT: (2)

Answer 47

1. PARALLEL 2. ANTI-PARALLEL

Question 48

TYPES OF SPIN: (ANGULAR MOMENT)

Answer 48

1. CLOCKWISE 2. COUNTERCLOCKWISE