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Biophysics > Practical > Flashcards

Practical Flashcards

1
Q

which of the following doesn’t describe(apply to?) experimental measurement :

A. all measurements are approximations- no physical quantity can be measured with perfect certainty; there is always errors in any measurement.
B. repeated measurements of a quantity can stray from the quantity’s true value.
C. the accuracy and precision can be improved when repeating an experiment with random error
D. the accuracy can be improved when repeating the experiment in systematic error

A

The accuracy can be improved when repeating the experiment in systematic error

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2
Q

Light does not need a medium to propagate. Which of the followings explains why light can travel in empty space:

A. because light is a collection of particles
B. because light is an electromagnetic wave
C. because light reflects and refracts

A

because light is an electromagnetic wave

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3
Q

What happens is true in endoscopy?

A. it undergoes repeated total internal reflection
B. the core has a lower index of refraction
C. the cladding has a higher index of refraction

A

It undergoes repeated total internal reflection

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4
Q

Which of the following describe the emission line spectra of atoms

A. emission line spectra consists of wavelengths of light in the visible reigon only
B. hydrogen has the simplest emission of all other elements
C. discrete line spectra are due to the existence of many ground states
D. discrete line spectra are due to interactions with neighboring atoms

A

Hydrogen has the simplest emission of all other elements

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5
Q 
what type of energy is transferred by electromagnetic wave from a hot campfire? 
A. radiation
B. convection 
C. conduction 
D. combustion
A

radiation

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6
Q

what does the continuity law composed of
A. conservation of mass
B. conservation of velocity
C. conservation of energy

A

conservation of mass

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7
Q

what does the acronym laser stand for?

A- light absorption by stimulated emission for radiation
B- light amplification by stimulated emission for radiation
C- light absorption by spontaneous emission of radiation
D- light amplification by spontaneous emission of emission

A

light amplification by stimulated emission for radiation

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8
Q

what are the characteristics of laser?

A- coherent, monochromatic, multidirectional
B- noncoherent, monochromatic, multidirectional
C-coherent, multicolored, directional
D- coherent, monochromatic, directional

A

coherent, monochromatic, directional

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9
Q

the right arrangement of how sound propagate through materials from lower speed to higher speed

A- Liquid, solid, gas
B- Gas, liquid, solid
C- Gas, solid, liquid
D- Solid, liquid, gas

A

Gas, liquid, solid

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10
Q

Which of these errors couldn’t be controlled in the experiment ?

A) Instrumental error
B) Systematic error
C) Random error
D) Force error

A

Random error

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11
Q

What is the shortest wavelength in the Balmer series

A

364nm

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12
Q

What is the name of heat transfer by mass movement of molecules from a place to another

A) Conduction
B) Convection
C) Radiation

A

Convection

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13
Q

Which of the following is a characteristic of a laser:

A.Monochromatic
B. directional
C. coherent

A

directional

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14
Q

Arrange the speed of sound from slowest to fastest

A) Gas/liquid/solid
B) Solid/gas/liquid
C) Gas/solid/liquid
D) Liquid/solid/gas

A

Gas/liquid/solid

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15
Q

What are the properties of light from lasers

A) Coherent, many wavelengths, multidirectional
B) Coherent, many wavelengths, directional
C) Coherent, monochromatic, multidirectional
D) Coherent, monochromatic, directional

A

Coherent, monochromatic, directional

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16
Q

What does the speed of sound depend on

A) Stiffness & Viscosity
B) Density & Stiffness
C) Density & Viscosity
D) Viscosity & Compressibility

A

Density & Stiffness

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17
Q

What does acronym laser stand for?

a) Light absorption by stimulated emission of radiation
b) Light absorption by spontaneous emission of radiation
c) Light amplification by stimulated emission of radiation
d) Light amplification by spontaneous emission of radiation

A

Light amplification by stimulated emission of radiation

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18
Q

what is the correct order of increasing (from slowest to fastest ) the propagation of the speed of sound ?

A) solid, liqiud, gas
B) gas, liquid, solid
C) gas, solid, liquid
D) liquid, gas, solid

A

gas, liquid, solid

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19
Q

what is the shortest wavelength (in nm) observed in the spectrum of hydrogen in the Paschen spectral series?

a) 97
b) 122
c) 400
d) 820

A

820

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20
Q

What is the phenomena on which fiber optics are based on

A)reflection modulation
B) Total internal reflection
C) chromatic aberration
D) population inversion

A

Total internal reflection

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21
Q

What does the speed of sound depend on?

a) stiffness and viscosity
b) compressibility and viscosity
c) viscosity and density
d) stiffness and density

A

stiffness and density

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22
Q

When does acoustic shadowing occur

a) High attenuation surface
b) Low attenuation surface
c) Low reflection surface
d) High absorptio

A

High attenuation surface

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23
Q

Which statement best explains the term hyperechoic in the context of ultrasound

a) The image is darker than the surroundings
b) The image is brighter than the surroundings
c) The image is as bright as the surroundings
d) An echo free image

A

The image is brighter than the surroundings

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24
Q

What is the composition of the Braking X-Rays

a) continous spectrum at a specific frequency
b) Specific spectrum
c) Continuous spectrum at any frequency
d) Radiation of only one energy

A

Continuous spectrum at any frequency

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25
Q

When the electron hit into the tungsten target, what percentage
of X-rays will be emitted

a) 100%
b) 99%
C) 50%
d) 1%

A

1%

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26
Q

What is given off the most when electrons hit the tungsten target

a) X-rays
b) Heat
c) Light
d) Sound waves

A

Heat

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27
Q

Why do we use tungsten as a target for X-ray foundation

a) it is cheap
b) it has a high atomic number
c) it can withstand heat
d) it is shiny

A

it has a high atomic number

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28
Q

What do photocathodes do in an image intensifier of an x-ray

a) They convert heat to light
b) They convert light to heat
c) They convert light to electrons
d) They convert electrons to light

A

They convert light to electrons

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29
Q

in the context of MRI, what is the name of the recovery of the
longitudinal magnetization ?

a. TR recovery
b. TE recovery
c. T1 recovery
d. T2 recovery

A

T1 recovery

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30
Q

2-which of the following represents an example of Static
contrast?

a. MRA
b. Chemical shift imaging
c. Perfusion weighted contrast
d. Diffusion weighted contrast

A

Chemical shift imaging

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31
Q

within the context of MRI, which design can generate a homogenous magnetic field with the use of 2 circular current loops that are separated by a distance equal to the distances of their radius

a. Solenoid double design
b. Helmholtz pair design
C. Solenoid triple pair design
d. Golay pair design

A

Helmholtz pair design

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32
Q

when sinc function returns to time domain what is the shape of the graph

a. single frequency
b. sinusoid
c. tophat
d. cosine graph

A

tophat

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33
Q

how long does T1 recovery last for?

a. a few seconds
b. a few milliseconds
c. a few nanoseconds
d. a few picoseconds

A

a few seconds

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34
Q

6-What is a key characteristic of MRI imaging?

a) It uses ionizing radiation therefore it is more harmful
b) It does not use ionizing radiation therefore it is more harmful
c) It does not use ionizing radiation therefore it is less harmful
d) It uses ionizing radiation therefore it is less harmful

A

It does not use ionizing radiation therefore it is less harmful

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35
Q

within the context of MRI, how is it possible to select the slice
wanted with different location and thickness?

a) By using only 1 gradient
b) By increasing magnetic field strength
c) By heating the coils before taking the image
d) By using different gradients together

A

By using different gradients together

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36
Q

If we selected long TE and short TR, what will the resulting
image be?

a) T1 weighted
b) Useless
c) T2 weighted
d) Proton density weighted

A

PD

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37
Q

what is nuclear magnetic resonance (NMR)?

a) An electromagnetic coil that measures the energy emitted
back to the environment after its initial absorption by the sample
b) The technique that allows the collection of 2D images by
changing spatial gradients, following a single electromagnetic pulse from a transmitter
c) The measurable changes of magnetic properties of atomic
nuclei by applying an oscillating magnetic field at the resonant frequency of the nuclei
d) A magnetic field whose strength varies systematically over space

A

The measurable changes of magnetic properties of atomic
nuclei by applying an oscillating magnetic field at the
resonant frequency of the nuclei

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38
Q

What is the spatial gradient?

a. An electromagnetic coll that measures the energy emitted
hack to the environment atter its initial absorotion of the sample
b) The technique that allows the collection or 2U images by
changing spatial gradients, following a single electromagneuc pulse from a transmitter
c. The measurable changes of magnetic properties of atomic
nuclel by applying an oscillating magnetic field at the resonant frequency of the nuclei
d) A magnetic field whose strength varies systematically over space

A

A magnetic field whose strength varies systematically over space

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39
Q

12- what do you get from a sinusoid after fourier transform is applied in the time domain?

a) Single frequency
b) Top hat
c) Larmor frequency
d) Sinc function

A

Single frequency

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40
Q

what is true about gradient fields

a) They change the strength of the magnetic field but not the
direction
b) They change the strength of the magnetic field and the
direction
c) They do not change both the strength of the magnetic field and the direction
d) They do not change the strength of the magnetic field but they change the direction

A

They change the strength of the magnetic field but not the

direction

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41
Q

what is used to obtain an image from K space

a) fourier transform
b) larmor frequency
c) Inverse Fourier transform
d) Gradients

A

Inverse fourier transform

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42
Q

what forms the basis of fMRI contrasts?

a) t1
b) t2
c) t2*
d) TE

A

t2*

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43
Q

what is the time interval between 2 successive excitation pulses?

a) TE
b) TR
c) T2*
d) T1

A

TR

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44
Q

The magnetic moment for a spinning proton is generated by

a) the electric current induced by rotating charge
b) the magnetic field induced by the MRI
c) the spatial gradients
d) the x-ray machine

A

the electric current induced by rotating charge

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45
Q

gradient magnetic fields generate electric current within the body because

a) The human body is a conductor
b) The human body is a heat transmitter
c) The gradient fields are too strong
d) The human body is an incubator

A

The human body is a conductor

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46
Q

what is the current measured on a detector coil following excitation and reception

a) RF coil
b) Shimming coil
c) MR signal
d) Deduced signal

A

MR signal

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47
Q

a static magnetic field is a magnetic field whose intensity

a) changes over space and time
b) changes over space but not time
c) Changes over time but not space
d) does not change over space and time

A

does not change over space and time

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48
Q

what is the name of the frequency of oscillation that provides maximum energy transfer to the system

a) Resonant frequency
b) Received frequency
c) Reflected frequency
d) refraction frequency

A

Resonant frequency

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49
Q

what is the name of the center part of the MRI machine

a) door
b) hole
c) bore
d) Pore
e) big circle in the middle

A

bore

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50
Q

what is the time constant that describes the recovery of the
longitudinal component of net magnetization?

a) T1
b) T2
c) TR
d) TE

A

T1

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51
Q

What is true about T2 and T2*

a) T2 is faster than T2*
b) T2 is slower than T2*
c) T2 and T2* are the same speed
d) WHATS T2*

A

T2 is slower than T2*

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52
Q

if RF coils resistance is decreases, what happens to the coil?

a) Sensitivity decreases
b) Sensitivity increases
c) Inductance increases
d) Capacitance increases

A

Sensitivity increases

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53
Q

within the context of MRI, Short TE and Short TR results in

a) T1 contrast
b) T2 contrast
c) T2* contrast
d) PD contrast

A

T1 contrast

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54
Q

within the context of MRI, which statement is FALSE?

a) If TR is short and TE is short, it will maximize the T1 contrast and minimize the T2 contrast
b) If TR is long and TE is long, it will minimize the T1 contrast
and maximize the T2 contrast
c) If TR is short and TE is long, the image will be PD weighted
d) If TR is long and TE is short, the image will be PD weighted

A

If TR is short and TE is long, the image will be PD weighted

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55
Q

What is the minimal number of gradients usually used in MRI

a) 1
b) 2
c) 3
d) 4

A

3

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56
Q

Which of the following is true
a) Each gradient is relevant to its axis and does not change the magnetic field
b) Each gradient is relevant to its axis and does change the
strength of the magnetic field
c) Each gradient is perpendicular to its axis and does not change the strength of the magnetic field
d) Each gradient is perpendicular to its axis and does change the strength of the magnetic field

A

Each gradient is relevant to its axis and does change the

strength of the magnetic field

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57
Q

which statement appropriately defines MR signal

a) Electromagnetic coils that create controlled spatial variation in the strength of the magnetic fields (gradient coils)
b) The current measured in a detector coil following excitation
and reception
c) Electromagnetic coils that generate and receive signals (
RFcoils)
d) The current measured in the detector coil after excitation
only

A

The current measured in a detector coil following excitation

and reception

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58
Q

What is the name of the frequency of oscillation that provides the maximum energy transfer to the system

a) Reflected frequency
b) Resonant frequency
c) Absorbed frequency
d) Rejected frequency

A

Resonant frequency

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59
Q

which statement best describes the T1 period

a) It is measured in an order of a few seconds
b) It is measured in an order of a few milliseconds
c) It is measured in an order of a few microseconds
d) It is measured in an order of a few nanoseconds

A

It is measured in an order of a few seconds

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60
Q

what is net magnetization?

a) The amount of energy released by the x-ray machine
b) The sum of magnetic moments of all the atoms
c) The sum of magnetic moments in a hydrogen atom

A

The sum of magnetic moments of all the atoms

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61
Q

which of the following can be categorized into static contrasts

a) MRA
b) TE
c) T1
d) TR

A

T1

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62
Q

how can we change the thickness of a slice

a) by changing the slope of the gradient and the same radio frequency can be used to select a different location
b) by using reverse fourier transform
c) by using both an MRI and x-ray machine simultaneously
d) by injecting radioactive isotopes into the patient prior to the
examination

A

by changing the slope of the gradient and the same radio frequency can be used to select a different location

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63
Q

which function will we obtain if we use inverse fourier transform on a sinc function

a) sinusoid
b) single frequency
c) top hat
d) fourier transform

A

top hat

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64
Q

a short TR and a long TE will give a

a) non-usefull image
b) T1
c) T2
d) PD

A

non-usefull image

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65
Q

which of the following creates a stron magnetic field that can generate a homogenous magnetic field

a) Golay pair
b) Hemholtz pair
c) Solenoid double
d) Solenoid single

A

Hemholtz pair

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66
Q

MRI uses

a) non ionizing energy
b) ionizng energy
c) partially ionizing energy
d) lasers

A

non ionizing energy

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67
Q

which statement best describes the term ‘excitation’

a) receiving electromagnetic energy from a sample at its
resonant frequency
b) receiving electromagnetic energy from a sample at its
reflected frequency
c) sending electromagnetic energy to a sample at its absorbed
frequency
d) sending electromagnetic energy to a sample at its resonant frequency

A

sending electromagnetic energy to a sample at its resonant frequency

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68
Q

how can a strong magnetic field, which can be generated with minimal electrical power requirements, be created

a) by using cryogens to cool the MRI scanner room
b) by cooling the X-ray machine
c) by cooling the electromagnets to near absolute zero
d) by cooling the electromagnets to room temperature

A

by cooling the electromagnets to near absolute zero

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69
Q

what happens if we increase R and C

a) the sensitivity will decrease
b) the sensitivity remains the same
c) The sensitivity will increase
d) The sensitivity is so sensitive

A

the sensitivity will decrease

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70
Q

What do you get from a sinusoid after forier transform is applied in the time domain?

a. single frequency
b. Top hat
c. Larmor freq
d. sinc function

A

single frequency

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71
Q

Which is true about gradient fields?

a. they change the strength of the magnetic field but not the direction
b. they change the strength and direction of the magnetic field
c. they do not change the strength, they only change the magnetic field direction

A

they change the strength of the magnetic field but not the direction

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72
Q

What is used to get an image from k space?

a. Forier transform
b. inverse forier transform
c. both forier transform and inverse forier transform

A

inverse forier transform

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73
Q

What forms the basis of fMRI BOLD contrast?

a. T1
b. T2
c. T2*
d. MRA

A

T2*

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74
Q

What is the time interval between 2 successive excitation pulses?

a. TE
b. T2
c. TR
d. T1

A

TR

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75
Q

The magnetic moment for a spinning proton is generated by

a. the electric current induced by rotating charge
b. the magnetic field induced by the MRI

A

the electric current induced by rotating charge

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76
Q

Gradient magnetic fields generate electric current within the body because

a. the human body is a conductor
b. the human body is a incubator
c. the gradient magnetic fields are too strong

A

the human body is a conductor

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77
Q

What is the purpose of the gradient coils?

a. to cause the MR signal to become spatially dependent in a controlled fashion
b. to cause the MR signal to become spatially independent in a controlled fashion
c. to cause the F coil to become spatially dependent in a controlled fashion
d. to cause the RF coil to become spatially independent in a controlled fashion

A

to cause the MR signal to become spatially dependent in a controlled fashion

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78
Q

What is the current measured on a detector coil following excitation and reception?

a. MR signal
b. RF coil
c. shimming coil
d. transmitter coil

A

MR signal

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79
Q

A static magnetic field is a magnetic field whose intensity

a. does not change over space but changes over time
b. does not change over space nor time
c. does not change over time but changes over space
d. changes over space and time

A

does not change over space nor time

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80
Q

What is the name of the frequency of oscillation that provides maximum energy transfer to the
system?

a. resonant frequency
b. absorbed frequency
c. armor frequency

A

resonant frequency

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81
Q

J.J Thompson’s experiment showed that?

a. cathodes give out negatively charged particles
b. cathodes give out positively charged particles
c. Anodes give out - charged particles.

A

cathodes give out negatively charged particles

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82
Q

Which of the following cant be true?

a. n=1, 1=0, ml =1, ms=1/2
b. n=2, I=1, ml = 0, ms=-1/2
c. n =3. I= 2, ml= -1, ms =-1/2
d. n=5, 1=3, ml=0, ms=1/2

A

n=1, 1=0, ml =1, ms=1/2

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83
Q

Which of the following wavelengths has the highest energy of a photon?

a. 500 lambda
b. 300 lambda
c. 800 lambda

A

300 lambda

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84
Q

According to de Broglie, what’s the order of lambda from the shortest to longest:

a. airplane - bullet - proton - electron
b. bullet - airolane - proton - electron
c. airplane - bullet -electron - proton

A

airplane - bullet - proton - electron

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85
Q

What is the name of the center part of MR..

a. bore
b. hole
c. door
d. core

A

bore

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86
Q

Which one of the following will give you a physical base quantity?

a. M^(-1) L^(2) T^(1)
b. M^(0) L^(0) T

A

M^(0) L^(0) T

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87
Q

The visible spectrum wavelengths are.

a. 200- 400 lambda
b. 400- 600 lambda
c. 350 - 750 lambda

A

350 - 750 lambda

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88
Q

If you increase the voltage across an x-ray tube to 100 k Which of the following is true?

a. the minimum energy of the x-rav spectrum = 100 kV
b. the maximum energy or the x-ray spectrum= 100 kV
c. energy will not change

A

the maximum energy or the x-ray spectrum= 100 kV

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89
Q

Why do we choose tungsten as a target for x-ray foundation!

a. it is cheap
b. it has high atomic number
c. it does not get heated quickly

A

it has high atomic number

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90
Q

Braking X- rays give you

a. continuous spectrum
b. specific spectrum

A

continuous spectrum

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91
Q

What do photocathodes do in an image intensifier of an x-ray?

a. they convert x-ray to light
b. they convert light to x-ravs
c. they convert light to electrons

A

they convert light to electrons

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92
Q

What is the time constant that describes the recovery of the longitudinal component of net magnetization:

a. T1
b. T2
c. T2*
d. PI

A

T1

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93
Q

Which gives you velocity of sound in order (from low to high)

a. solid liquid gas
b. gas liquid solid
c. gas solid liquid

A

gas liquid solid

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94
Q

Which of the following is true?

a. nucleus contains protons and neutrons
b. some. not all, matter is made of atoms
c. electrons are not affected ov electric magnetic force

A

nucleus contains protons and neutrons

95
Q

which is true about T2 and T2*?

a. T2 faster than T2*
b. T2 slower than T2*
c. they are the same

A

T2 slower than T2*

96
Q

What is the composition of x-rays?

a. Specific spectrum
b. Continuous spectrum

A

Continuous spectrum

97
Q

If RF coil s resistance is decreased, what happens to the coil?

a. Sensitivity (Q) increases
b. Sensitivity (Q) decreases
c. Inductance (L) and capacitance(C) increases
d. Capacitance (C) increases

A

Sensitivity (Q) increases

98
Q

In the context of MRI short TE and TR means what?

a. T1 contrast
b. T2 contrast
c. T2* contrast
d. PD contrast

A

T1 contrast

99
Q

Which of the following about MRIs true?

a. If TR Is Short. TE is short. It will maximize the TI contrast and minimie the T2 contrast
b. If TR is long, TE is long, it will minimize the T1 contrast and maximize the T2 contrast

A

If TR Is Short. TE is short. It will maximize the TI contrast and minimie the T2 contrast

100
Q

What is the relationship between attenuation coefficient and the atomic number of Compton Effect

a. u is independent of z

b. u is proportional to z
c. u Is proportional to z^2
d. u is proportionalto z^3

A

u is independent of z

101
Q

What’s the minimal number of gradients usually used in MRI

a. 1
b. 2
c. 3
d. 4

A

3

102
Q

What is true regarding MRI gradient?

a. Each gradient is relevant to its axis and does not change the strength of the magnetic field
b. Each gradient is relevant to its axis and changes the strength of the magnetic field
c. Each gradient is perpendicular to the axis and changes the strength of the magnetic field
d. Each gradient is perpendicular to the axis and does not change the strength or the magnetic field

A

Each gradient is relevant to its axis and changes the strength of the magnetic field

103
Q

Which one of the following is right about accurate and precise.

a. In accurate measurement. the value is not the same as true value
b. The accuracy of the measurement depends on the instrumentthacis used
c. In precise measurement, the measurement does not give near identical values
d. Scientists want precise measurement but not accurate

A

The accuracy of the measurement depends on the instrumentthacis used

104
Q

What is the name of the frequency of oscillation that provides the maximum energy transfer to the system

a) Reflected frequency
b) Resonant frequency
c) Absorbed frequency
d) Rejected frequency

A

Resonant frequency

105
Q

which statement best describes the T1 period

a) It is measured in an order of a few seconds
b) It is measured in an order of a few milliseconds
c) It is measured in an order of a few microseconds
d) It is measured in an order of a few nanoseconds

A

It is measured in an order of a few seconds

106
Q

what is net magnetization?

a) The amount of energy released by the x-ray machine
b) The sum of magnetic moments of all the atoms
c) The sum of magnetic moments in a hydrogen atom

A

The sum of magnetic moments of all the atoms

107
Q

which of the following can be categorized into static contrasts

a) MRA
b) TE
c) T1
d) TR

A

T1

108
Q

how can we change the thickness of a slice

a) by changing the slope of the gradient and the same radio frequency can be used to select a different location
b) by using reverse fourier transform
c) by using both an MRI and x-ray machine simultaneously
d) by injecting radioactive isotopes into the patient prior to the
examination

A

by changing the slope of the gradient and the same radio frequency can be used to select a different location

109
Q

which function will we obtain if we use inverse fourier transform on a sinc function

a) sinusoid
b) single frequency
c) top hat
d) fourier transform

A

top hat

110
Q

a short TR and a long TE will give a

a) non-usefull image
b) T1
c) T2
d) PD

A

non-usefull image

111
Q

Which constant depends on magnetic field strength and type of tissue to realign spin with external magnetic field?

a. T1
b. T2
c. TR
d. TE

A

T1

112
Q

An incident rav trom air to glass has an angle of 30. find the angle atter it passes through the glass

a. 56 away from the normal
b. 50 towaras the normal
c. 18 away from the normal
d. 18 towards the normal

A

18 away from the normal

113
Q

Comparing to λ red photon a blue photon has

a. A blue photon has longer λ, less frequency, less energy
b. A blue photon has longer λ, high frequency, higher energy
c. A blue photon has shorter λ, less frequency, less energy
d. A blue photon has shorter λ, higher frequency, higher energy

A

A blue photon has shorter λ, higher frequency, higher energy

114
Q

When using high power densitv laser of ultraviolet wavelenath some chemical bonds can be broken, causing local heating. This process called

a. Photochemical
b. Photo-coagulation
c. Photo- vanorization
d. General heating

A

Photochemical

115
Q

If the TR= 100 and the TE= 12 what Is the contrast?

a. T1
b. T2
c. PD
d. T2*

A

PD

116
Q

What’s the longest wavelength in balmar series

A

656 nm

117
Q

Which of the following is true regarding the line spectrum?

a. Bhor’s model of the atom couldn’t explain the line spectrum or H atom
b. The line spectrum emitted by all heated sollds, liquids, and dense gases
c. The line spectrum of heated low density gases emits light at specinic wavelengths
d. The line spectrum emits light at all wavelengths

A

The line spectrum of heated low density gases emits light at specinic wavelengths

118
Q

Farsightedness use:

A

Positive power of foca/llenst

119
Q

In the context or MRI, what is the name or the recovery or the longitudinal magnetization :

a- TR recovery
b- TE recoverv
c- T1 recovery
d- T2 recovery

A

T1 recovery

120
Q

Acoustic shadowing

A

High attenuation surface.

121
Q

What does the right-hand rule determine

A

it determines the angular velocity

122
Q

Within the context of MRI. which design can generate a homogenous magnetic field with the use of 2 circular current loops that are separated by a distance equal to the distances or their radius

a-solenoid double design
b-Helmholtz pair design
c- solenoid triple pair design
d- golay pair design

A

Helmholtz pair design

123
Q

What is magnetic moment?

A

the torque exerted on a magnet

124
Q

When sinc function returns what haopens to the time domain?

A

Top hat

125
Q

What is the longest wavelength of the palmers series?

A

656

126
Q

Which Instrument will ave vou homogenous pair, the radius = the distance between them, pair of loops

A

helmholtz pain

127
Q

T1 Recovery duration?

A

few seconds

128
Q

What is considered a true statement

a- ionizing radiation has higher energy and frequency and wavelength than non-ionizing radiation
b- ionizing radiation has higher energy and frequency and lower wavelength than non-ionizing radiation
c- ionizing radiation has lower enerav and frequency and higher wavelength than non-ionizing
radiation

A

ionizing radiation has higher energy and frequency and lower wavelength than non-ionizing radiation

129
Q

How is MA is related to Z in Compton scattering?

A

MA IS independent from Z

130
Q

Which of the following wave lengths has the highest energy of a photon?

2-800
b-400
c-500
d-700

A

400

131
Q

What is the order or density Is the speed or sound raster!

A

solid, liquid, gas

132
Q

Bernoull’s equation depends on:

A

mass conservation, energy conservation

133
Q

Whats the relation between Compton and attenuation coeticient:

A

attenuation coefficient is dependent of Z

134
Q 
Arrange propagation speed from the lowest to the highest:
a- solId, liquid, gas
b- gas, liquid solid
c- liquid, gas, solid
d. gas, solid, liquid
A

solId, liquid, gas

135
Q

Which of the followina is a static contrast

a- MRA
b- T1
c- TE
d- T2

A

T1
and
T2

136
Q

Why is the emission spectrum is a characteristic of the material and can serve as a type of fingerprint to identify gases?

a- because all gases emit the same wavelength of line spectrum
b-only light at certain wavelenaths are emitted
c- they are unique

A

only light at certain wavelenaths are emitted

137
Q

What is a characteristic of MRI imaging:

  • uses ionizing radiation
  • uses non-ionizing radiation.
A

uses non-ionizing radiation

138
Q

What is the longest wavelength in Balmer series?

2-420
b-656
c-1850

A

656

139
Q

What’s the wavelength range of visible light?

A

750nm to 380nm

140
Q

In MRI, how is it possible to select the slice with different location and thickness?

A

Different gradient

141
Q

long TE, short TR? What is the image?

A

we cannot make image

142
Q

what is NMR?

A

Nuclear Magnetic Resonance (NMR): The measurable changes in magnetic properties of atomic nuclei induced by the application of an oscillating magnetic field at the resonant frequency or the nuclei

143
Q

What is the “spatial gradient”?

A

special gradient is magnetic felid whose strength varies systemically over the space.

144
Q

Systematic errors ead to the reduction of

a -Precession in measurements
b- Significant figures in measurements
c- Accuracy in measurements

A

Accuracy in measurements

145
Q

What is the composition of x-rays produced by “braking” type?

a- a small number or delinea energies
b- continuous spectrum
c- radiauon or on one enera onoton
d- specific spectrum

A

continuous spectrum

146
Q

what explains the hyperchoic in context of ultrasound?

a- image darker than the surroundings
b- image brighter than the surroundings
c-image as bright as the surroundings
d-image without echoes (echo free)

A

image brighter than the surroundings

147
Q

In MRI, what is the minimum amout of gradients used?

A

3

148
Q

In MRI, what Is the time interval between successive excitation pulses?

A. TR
B. TE
C. T1

A

TR

149
Q

In MRI, what is the time constant that depends on magnetic field strength
and type of tissue and indicates time taken to realign with the external
magnetic field?

A. T2
B. T1
C. TE
D. TR

A

T1

150
Q

In the context of MRI, short TE and short TR create which type of image?

A. T1 weighted
B. T2 weighted
C. PD weighted
D. T2* weighted

A

T1 weighted

151
Q

What is true regarding T2 and T2*?

A. T2 decay is faster than T2* decay
B. T2 decay is slower than T2* decay
C. they are the same
D. T2* decay is double the T2 decay

A

T2 decay is slower than T2* decay

152
Q

The ideal static magnetic field has:

A. an intensity that does not change over space only
B. an intensity that does not change over space or time
C. an intensity that changes over time and space

A

an intensity that does not change over space or time

153
Q

The frequency of oscillation that provides maximum energy transfer to the system is:

a. resonant frequency
b. reflected
c. repeated
d. resting

A

resonant frequency

154
Q

The frequency of oscillation that provides maximum energy transfer to the system is:

a. resonant frequency
b. reflected
c. repeated
d. resting

A

resonant frequency

155
Q

The relationship between the attenuation coefficient of Compton
scattering and the atomic number (Z):

A. the attenuation coefficient of Compton scattering is proportionate to Z
B. the attenuation coefficient of Compton scattering is proportionate to Z12
C. the attenuation coefficient of Compton scattering is proportionate to Z^3
D. it is independent of Z

A

it is independent of Z

156
Q

What is true about atoms?

A. not all matter is composed of atoms
B. different atoms have the same nuclear compositions
C. the nucleus contains protons and neutrons

A

the nucleus contains protons and neutrons

157
Q

What changes the speed of sound?

A. wavelength
B. frequency
C. amplitude
D. medium

A

medium

158
Q

What generates the magnetic moment in spinning protons?

A. the electric current which is induced by rotating charge
B. the movement of its internal magnetic field

A

the electric current which is induced by rotating charge

159
Q

What is the current measured in a detector coil following excitation and
reception?

A

MR signal

160
Q

What is the central tube of MRI called?

A. core
B. bore
C. RF coil

A

bore

161
Q

In radio frequency (RF) coils, if the resistance is decreased, what
happens to the coil sensitivity (Q)?

A. the sensivity increases
B. the sensitivity decreases

A

the sensiviv increases

162
Q

What is true regarding MRI gradients?

A. each gradient is relevant to its axis and changes the strength and direction
of the magnetic field
B. each gradient is relevant to its axis and only changes the strength of the
magnetic field
C. each gradient is perpendicular to the axis and changes the strength of the
magnetic field

A

each gradient is relevant to its axis and only changes the strength of the magnetic field

163
Q

If TR= 2000 and TE=30 what will the image be?

A. T1 weighted
B. T2 weighted
C. T2* weighted
D. PD weighted

A

PD weighted

164
Q

What is the percentage of ultrasound reflected in “air-fat”boundary? Zair= 400 , Z fat= 1.3x10^6

A. 99%
B. 1%

A

99%

165
Q

The speed of sound wave depends on the :

A. medium
B. frequency

A

medium

166
Q

When measuring the mass quantity of the salt once using the balance 16.43 (g)

A. 16.430 ‡ 0.001 g
B. 16.43 ‡ 0.01 g
C. 16.34 g

A

16.43 ‡ 0.01 g

167
Q

Which of the following describes MRI?

A. if TR is short, TE is short, it will maximize the effect of T1 differences and and minimize the effect of T2 differences
B. if TR long, TE is long, it will minimize the effect of T2 differences and maximize the effect of T1 differences
C. short TR, short TE minimize the effect of T1 differences and maximize the T2 differences
D. long TR, short TE minimize the effect of T1 differences and maximize the T2 differences

A

if TR is short, TE is short, it will maximize the effect of T1 differences and and minimize the effect of T2 differences

168
Q

Short TE and short TR in MRI?

A. T1 weighted image
B. T2 weighted image
D. PD weighted image

A

T1 weighted image

169
Q

What best describes the intensity of the ideal static magnetic field ?

A. doesn’t change over space nor time
B. changes over space but doesn’t over time
C. doesn’t change over space but change over time
D. changes over space and time

A

doesn’t change over space nor time

170
Q

in the context of MRI what represent the time between successive
excitation pulses?

A. T1
B. T2
C. Tr
D. Te

A

Tr

171
Q

In context of mri, the ideal static magnetic field is characterized by in
terms of the intensity ?

A. changes over space and time
B. does not change over space and time
C. changes over space , but not over time
D. changes over time, but not space

A

does not change over space and time

172
Q

In the MRI context. what is the name of the current measured in the detector after excitation and reception

A

Mr signal

173
Q

Which best describes the atom:

A

The nucleus has protons and neutrons.

174
Q

What is differences between T2 wT2*

A. T2 is faster than T2*
B. TR is slower than T2*
C. T2 has the same velocity of T2*

A

TR is slower than T2*

175
Q

if the RF coil’s resistance decreases, what happens to the coil?

A. the sensitivity (Q) increases
B. the sensitivity (Q) decreases
C. the inductance (L) and the capacitance(C) increase
D. the capacitance (C) increases

A

the sensitivity (Q) increases

176
Q

in x-ray tube, the reason could decrease the minimum wavelength in the continuous spectrum is

A. the kinetic energy of the incident electron is increased
B. target is a higher atomic number
C. target is a lower atomic number
D. something about using a thin target rather than thick target

A

the kinetic energy of the incident electron is increased

177
Q

In context of MRI. What is the frequency of oscillation that provides
maximum energy:

A. armor frequency
B. resonant frequency

A

resonant frequency

178
Q

)If the thermal conductivity k increased by a factor of 5 , what change happens to the rate of heat loss ?

A. increases by a factor of 5
B. decreases by a factor of 5
C. Increases by a factor of 2
D. 1/2

A

increases by a factor of 5

179
Q

What is the highest frequency if a hydrogen atom absorbed energy and
was transmitted from a lower energy state to a higher energy state)

A. n:9 > n:6
B. n:6 > n:3
C. n:8 > n:5
D. n:13 > n:10

A

n:6 > n:3

180
Q

A patient is given a corrective lense of +1.75 diopter. What does the
patient suffer from.

A. Too short focal length
B. image forms after the retina
C. it is corrected with diverging lens
D. patient has myopia

A

image forms after the retina

181
Q

according to broglie, whats the order if wavelength from shortest to
longer?

A. bullet, proton, electron, photon
B. photon, electron, proton , bullet
C. bullet, photon , proton , electron

A

bullet, proton, electron, photon

182
Q

The magnetic moment for a spinning proton is generated by

A. The electric current induced by rotating charge
B. The magnetic field induced by the MRI

A

The magnetic field induced by the MRI

183
Q

which of the following is true regarding MRI gradient?

A. Each gradient is relevant to its axis and does not change the strength of
the magnetic field.
B. Each gradient is relevant to its axis and changes the strength of the
magnetic field
C. Each gradient is perpendicular to the axis and changes the strength of the
magnetic field
D. Each gradient is perpendicular to the axis and does not change the
strength of magnetic field.

A

Each gradient is relevant to its axis and changes the strength of the
magnetic field

184
Q

what is the MLT formula for a and b

V= a+bt

A

M^OL ^1T^-1 , M^OL^1T1-2.

185
Q

In compton scattering whats the relation between M and z

A

M is independent of Z

186
Q

What is the process or heat transter ov the mass movement of molecules from one place to another?

a. Convection
b. Conduction
c. Radiation
d. Combustion

A

Convection

187
Q

What will haopen to flow it the viscosity is doubled and the length is halved

a. 1
b. 2
c. 4
d. 8

A

1

188
Q

What is a technique used in MRI with the off-resonance excitation pulse to saturate the MR signal from large molecules?

a. X-ray
b. Manti resonan
c. Magnetization transfer imaging
d. MR signal

A

Magnetization transfer imaging

189
Q

What is a visual description of how one or more quantities vary over space?

a. gradient
b. Image
c. Resonance
d. Echo

A

Echo

190
Q

If TR= 3000ms and TE= 15, what type of image is created?

a. T1
b. T2
c. T2*
d. PD

A

PD

191
Q

What will happen if vou decrease the resistance of the MR.

a. Increase of Q
b. Decrease of Q
c. Increase capacitance
d. Increase capacitance and energy

A

Increase of Q

192
Q

Which coil is effective for close regions and produces a sensitive image only in that region!

a. Volume coil
b. Surface coil
c. Shimming arrav coll
d. Multifunctional coil

A

Surface coil

193
Q

Which of the following is a factor that aftects the speed of sound

a. Frequency
b. Wavelength
c. Medium
d. Amplitude

A

Medium

194
Q

What is a nucleus with NMR properties called?

a. Proton
b. Neutron
c. Spin
d. Magnet

A

Spin

195
Q

An electron hits a target anode, which produces x-rays of 70eV energy. That means

a. Breaking x-rav with a minimum energy of 70eV
b. Breaking x-rav with a minimum energy of 70eV
c. Characteristic x-rav with a minimum enerav of 70eV
d. Characteristic -ray with a mean energy of 70eV

A

Breaking x-rav with a maximum energv of 70eV

196
Q

If the intensitv of a sound beam remains unchanged and the area is halved the power. the initial power is Po

a. 0.5 Po
b. 2 Po
c. 4 Po
d. Po

A

0.5 Po

197
Q

Bernoull’s equation is a consequence of.

a. Energy conservation
b. Mass conservation
c. heat conservation
d. Pressure conservation

A

Energy conservation

198
Q

If TR is short, and TE is short, then the image formed is

a. PD
b. T2*
c. T1
d. No image

A

T1

199
Q

How is MA is related to Z in photoelectric effect?

a. Independent
b. Dependent Z
c. Dependent Z^2
d. Dependent Z^3

A

Dependent Z^3

200
Q

Which type of ultrasound artifacts has a high level of attenuation:

a. Lateral cystic shadowing
b. Acoustic enhancement
c. Acoustic shadowing
d. Reverberation artifacts

A

Acoustic shadowing

201
Q

Which one or the following is a representation or K-space:

a. Sinc function
b. Top hat
c. Single trequenc
d. sinusoid

A

Sinc function

202
Q

A measure of the strength of a magnetic field over an area or space

a. Flux
b. Bo
c. Spin
d. C

A

Flux

203
Q

The ability to store electric charge:

a. Flux
b. Bo
c. Spin
d. C

A

Spin

204
Q

What is the dimensional formula of KE?

a. M^2 L T^2
b. M^-2 L T^2
c. M L^2 T^-2
d. M L T

A

M L^2 T^-2

205
Q

What is the direction of the static magnetic field?

a. Horzonal
b. Vertical
c. Longitudinal
D Perpendicula

A

Longitudinal

206
Q

What does armor trequency depend on

a) numper or gradients
b) number or spins In spin system
c) strength of the magnetic field
d) the angular of the magnetic field

A

strength of the magnetic field

207
Q

What is the purpose of the gradient coils?

a. to cause the MR signal to become spatially dependent in a controlled fashion
b. to cause the signal to become spallally Independent In a controlled fashion
c. to cause the Ar coll to become spatially dependent in a controlled tashion

A

to cause the MR signal to become spatially dependent in a controlled fashion

208
Q

ov what factor doe sthe blood flow change if the viscosity is doubled and the length of the vessel is halved

a) 1
b) 2
c) 4
d) 8

A

1

209
Q

What is the x-radiation production or braking process?

A

Continuous spectrum of energies

210
Q

Which type or Interaction with matter causes me X-ray pnoton to disappear and removes an electron from the atom

a) photoelectric effect
b) comoton scattering
c) pair production
a) elastic scattering

A

photoelectric effect

211
Q

what Is the process or Dolling on electron out or the milament or an xray tube

A

thermionic emissior

212
Q

After Fourier transformation sinusoid becomes :

A. Double frequenci
B. Too hat
C. Single frequency
D. Sinc function

A

Single frequency

213
Q

What factor affects the speed of sound

a) frequency
b) wavelength
c) medium
d) amplitude

A

medium

214
Q

Tr= 700 Te= 25

A) T1
B) T2
C) T2*
D) PD

A

T1

215
Q

What is the central tube in mri called?

A-Bore
B- Core
C- Door

A

Bore

216
Q

What are the properties of an ideal fluid?

a. Non viscous, laminar Incompressible
b. Non viscous, tulorent. compressible

A

Non viscous, laminar . Incompressible

217
Q

In the context of MRI what best describes the use of TR and TE?

A

Short TR and short Tr will maximize T1 diferences and Minimize T2 diferences

218
Q

In MRI, Why is gradient switching can generate small electric currents that have the potential to stimulate nerve and muscles, or alter function or implanted devices

A) because human body acts as conductor
b) because human body acts as insulator

A

because human body acts as conductor

219
Q

what forms a basis bold contrast in fmri?

a t contrast
b) t2* contrast
C) pd contrast

A

t2* contrast

220
Q

if TR is short TE is long, what will be the weighting of MRI image?

a) T2 weighted
b) T1 weighted
c) PD weighted
d) Not useful

A

Not useful

221
Q

what describes a nucleus in the context of MRI

a) a nucleus with either angular momentum or magnetic moment
b) a nucleus with both angular momentum and magnetic moment
c) a nucleus in NMR
d) a nucleus in NMR depends on the gradient magnetic field

A

a nucleus with both angular momentum and magnetic moment

222
Q

TR=short, TE=short

a) T1-weighted
b) T2-weighed
c) PD-weighted
d) not useful

A

T1-weighted

223
Q

whar spectrum does the X-ray effect when add filter

a) low energy
b) high energy

A

High energy

224
Q

ln context of MRI which is a mathematical technique(s) used to convert raw data from k-space to image space

a) Fourier transfom
b) Inverse fourier transform
c) a and b
d) Fourier transform and Bloch equation

A

Inverse Fourier transform

225
Q

a short TR and a long TE will give

A) T1
B) T2
C) PD
D) non useful image

A

non useful image

226
Q

In context of MRI, what is true regarding shimming coils

A) Shimming coils are always left on
B) Shimming coils are adjusted for each patient

A

Shimming coils are adjusted for each patient

227
Q

Within the context of MR. what is the best describe of ideal static magnetic field

a) does change over space but not over time
b) Does not change over space nor time
c) Does change over time nor space
d) Does change over space and time

A

Does not change over space nor time

228
Q

What is the amount of significant figures in the following measurement: weight : 78.45 Kg

a) 2
b) 3
c) 4
d) 5

A

4

229
Q

What is the dimensional formula of KE. KE = 1/2 mv^2 where m is the mass and v is the velocity?

A) ML^-2T^-2
B) ML^2T^-2
C) ML^-1T^-2
D) M^0LT

A

ML^2T^-2

230
Q

What is the time interval berween 2 successive excitation pulse

a) TE
b) T2
c) Tr
d) T1

A

Tr

231
Q

The Ideal static magnatic field has :

a) an intensity that doesnt change over space on
b) an intensity that doesnt change over space or time
c) an intensity that does change over space or time

A

an intensity that doesnt change over space or time

232
Q

he magnatic moment or spinning proton is generated by:

a) the electric current induced by rotating charge
b) the magnatic feild induced by the MRI

A

the electric current induced by rotating charge

233
Q

If RF coils resistance decreases what happen to the coil ?

a) the sensitivity Q increase
b) the sensitivity Q decrease
c) the inductance (L) and capacitance (C) increase
d) the capacitance Increase

A

the sensitivity Q increase

234
Q

What is the current measured on a detector coil followina excitation and reception

a) MR signals
b) RF coil
c) shimming coil
d) transmitter coil

A

MR signals

Biophysics (1 decks)

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