# Biofyz MCQ Answers (82 Q's)

version from 2016-06-28 19:31

## Section 1

Which of the following is heavier than a proton? Neutron
Hadrons are always the particles:Formed by combinations of quarks
Fermions are always the particles with: Non integer spin number
What is it called when an electron jumps from L to K shell?De-excitation
What is the photoelectric effect?Total energy transformation into an ejected electron
Energy of photons can be expressed by:E = h.f which is the same as… E= hc/λ
Viscosity is:Internal friction
Viscosity cannot be measured byCalorimetry viscometer AND Piezoelectric viscometer
For measuring concentration of different substances, we can’t useViscometry

## Section 2

Dynamic viscosity is independent ofLiquid density
Kinematic viscosity is independent of:Capillary shape AND Capillary length
Kinematic Viscosity is dependent of:Liquid density, dynamic viscosity & temperature
Surface tension (measured with stalagmometer):can be connected with capillary elevation BUT cannot explain the capillary elevation
Velocity of sound depends on the Medium
Hooke’s Law is: Elasticity of a medium
Physical half-life is expressed byTp = ln2/λ (ln2 = 0.693)
Best protection against beta-decayAluminium + Lead
Beer’s - Lambert´s law:I = Io .10^-εcx and refers to absorption
Absorption coefficient depends on:solvent AND wavelength
Dynamic viscosity is dependent on:liquid, shear stress & temperature

## Section 3

Which of the following can be used as an output device?Earphones
Dimensions of the sound intensity is: W/m2
We can hear:0,1 Wm^-2 AND 100db AND -10db
We cannot hear: -0,1 Wm-2 AND 0 Wm-2
How many Db is equal to 1 W/m-2? 120 dB
Weber – Fechner’s law can be connected with Audiometry
Acoustic impedance is independent ofBody temperature
What has the highest level of acoustic impedance?Lead
X- ray contrast agents areBaSo4 AND Iodine AND Substances containing heavy atoms
X-rays positive contrast agent cannot be:Protein´s suspension

## Section 4

Unsharpness of x–ray image cannot induce: Beta rays AND Gamma rays
A blurred x-ray image is caused by: Movement of the patient
Which method is the least harmful for patients?MRI
A patient with cochlear implants is not allowed in:MRI
Which imaging method is not allowed for patients with implants?MRI (depends on implant)
The Hounsfield unit for water is0
The Hounsfield unit for air is about: -1000
What is the Hounsfield unit of compact bone? 1000
The normal blood pressure is: 120mmHg/80mmHg

## Section 5

Decompression is caused by: Many gases dissolving in the blood
What treatment can be given to a deep sea diver:Hyperbaric chamber + oxygen
Blood pressure cannot be measured byErgometer AND Kropotkin method AND Catathermometer AND Thermocouple
Blood pressure can be measured byoscillometry
Blood pressure:cannot be measured with the thermocouple AND produce the Korotkoff´s sounds
Doppler methods can be used forstudy of moving structures (e.g. heart) AND velocity of blood flow
Doppler methods cannot be used forstudy of brain activity AND measuring body temperature AND study of electrical impulses
High frequency ultrasound can be produced bypiezoelectric transducers
For ultrasound imaging cannot be usedhyperbolic probes AND concave probes
Ultrasound echocontrast (agent) cannot besuspension of Ba2SO4

## Section 6

When examining deep body structures we have to use:high pulse repetition frequency and low ultrasound frequency
For deep tumours, Brachytherapy is not used body because:the radiation deviates in all directions
The “P” wave in the electrocardiogram (EKG) occurs during:atrial depolarisation
The alpha wave in electroenchephalogram occurs during the relax state
The delta wave in electroencephalogram occurs during:The pathological state
Chromatic aberration is caused by:light dispersion
Spherical aberration is caused by:thick lenses
What is the main function of the ciliary muscle? changing the curvature of the lens
Rheobase is:the lowest intensity which produce the stimulation

## Section 7

Chronaxy is the time factor of the double value of the rheobase
What is the unit for LET?Jm-1= J/m (eV.m-1)
What are the units of Greys (per second): Jkg-1 = J/kg -- for per second, J/kg/s
How many bits are in the binary number of 1000?4 bits
Proteins have information of?4 bits
Advantages of electron scanning microscope over transmission electron microscope?3D
What is the difference in magnification between a light microscope and a TEM?1000x
Thermistors:are semiconductor components with thermal dependence of resistance
What is a colposcope used for? Is actually used to examine vaginas
DNA molecule breaking bonds are hard due to? C-G
Which of the following are not methods of electrotherapy? Electrophoresis

## Section 8

C-14 and N-14 areIsobars
What kind of barrier is needed to separate the anode and cathode in a galvanic cell?semi permeable barrier
What is the physical principle of haemolysis (destroying red blood cells):None
What is the law that explains the difference between the boiling point of a pure liquid and a solution with the liquid as a solvent? None (actually ebullioscopy)
Thermocouples:are created by the junction of two different conductors
Thermovision can detectThyroid gland disorders
The best method used to stimulate nerve fibers: Galvanization
Scintillation counters must consist of a:Photomultiplier AND photocathode
Scintillation counters cannot consist of a:source of ionising radiation
RefractometryIs based on Snell`s Law
Which one of the following has the shortest wavelength Ultraviolet