1
Q
What does an oscilloscope measure?
A
Voltage vs time signals
2
Q
What does an oscilloscope NOT measure?
A
Acceleration of electrons
3
Q
What is thermionic emission?
A
Emission of electrons by highly heated substances
4
Q
What does ECG measure?
A
Electrical activity of the heart over time
5
Q
What structure is the pacemaker of the heart?
A
SA node
6
Q
What is the order of cardiac conduction?
A
SA node → AV node → Bundle of His → Purkinje fibers
7
Q
What formula estimates heart rate from ECG large squares?
A
HR = 300 / number of large squares between R waves
8
Q
What is an ECG lead?
A
Measurement of electrical potential difference between two electrodes
9
Q
What are the two types of ECG leads?
A
Bipolar and unipolar
10
Q
If paper speed is NOT 25 mm/s how do you calculate HR?
A
Find period T = RR/paper speed then HR = 60/T
11
Q
What causes repolarization in contractile cardiac cells?
A
Efflux of potassium ions
12
Q
What does the sodium-potassium pump require?
A
ATP
13
Q
What ions move out via the Na/K pump?
A
Sodium ions
14
Q
What ions move into the cell via the Na/K pump?
A
Potassium ions
15
Q
Which ion has the highest permeability at resting membrane potential?
A
Potassium
16
Q
What happens to cytoplasmic K+ during action potential?
A
Practically no change
17
Q
How is conduction in non-myelinated axons compared to myelinated?
A
Slower
18
Q
What increases propagation velocity in axons?
A
Larger axon diameter
19
Q
What do bipolar ECG leads measure?
A
Electrical potential difference between two points
20
Q
What happens to static pressure in a narrowed artery?
A
Decreases
21
Q
What happens to dynamic pressure in stenosis?
A
Increases
22
Q
What happens to static pressure when velocity increases?
A
Decreases
23
Q
Blood flows from narrow to wider vessel. Static pressure?
A
Increases
24
Q
Object density 800 kg/m³ in water. Float or sink?
A
Floats
25
Object density 1200 kg/m³ in water. Float or sink?
Sinks
26
What happens to pressure with depth in a fluid?
Increases
27
Hydraulic press law
Pascal's Law
28
Force formula in hydraulic press
F1/A1 = F2/A2
29
Fluid with highest viscosity
Honey
30
When does turbulent flow occur?
High Reynolds number
31
What is laminar flow?
Smooth parallel layers of fluid
32
Pressure at same depth in different containers
Same pressure
33
Pressure increase underwater rule
Every 10 m adds ~1 atm
34
Pressure at 20 m depth
3 atm
35
Pressure at 40 m depth
5 atm
36
Depth for total pressure 6 atm
50 m
37
Oxygen concentration at 50 m depth
~6 times higher
38
Poiseuille law relationship
Flow ∝ radius⁴
39
If artery radius halves what happens to flow?
Decreases 16 times
40
Hydrostatic pressure formula
P = ρgh
41
What compounds are asymmetrically distributed in membranes?
All compounds
42
Which pump requires ATP in membranes?
Na⁺/K⁺ pump
43
What causes rapid depolarization in neurons?
Voltage-gated sodium channels
44
What channels open in stretch receptors?
Mechanically gated channels
45
Primary function of cholesterol in membranes
Regulates membrane fluidity
46
Structure of phospholipid membrane
Hydrophilic heads outward, hydrophobic tails inward
47
Beer-Lambert law
I = I₀ e^(−αd)
48
Absorption coefficient formula
α = (1/d) ln(I₀/I)
49
Thickness formula
d = (1/α) ln(I₀/I)
50
What happens to intensity when absorber thickness increases?
Decreases exponentially
51
Half-value thickness definition
Thickness reducing radiation intensity to half
52
Half-value layer formula
μ = 0.693 / d₁/₂
53
Snell's law
n1 sinθ1 = n2 sinθ2
54
Light from air to water bends
Toward the normal
55
Polarization occurs in which waves?
Transverse waves
56
Refractive index formula
n = c/v
57
Speed of light in medium formula
v = c/n
58
Equivalent radiation dose formula
H = D × Q
59
LET definition
Energy deposited per unit distance
60
LET formula
LET = energy / distance
61
What is ionizing radiation?
Radiation capable of removing electrons
62
Example of non-ionizing radiation
Visible light
63
Most strongly ionizing radiation
Alpha particles
64
What produces Bremsstrahlung radiation?
Electron deceleration near nuclei
65
What happens in Compton scattering?
Photon collides with electron and loses energy
66
Photoelectric effect result
Electron ejected from atom
67
Definition of isotopes
Same protons, different neutrons
68
Beta minus decay change
Neutron → proton
69
Effective half-life formula
1/Te = 1/Tp + 1/Tb
70
What does effective half-life depend on?
Physical and biological half-life
71
Sound wave type
Longitudinal mechanical wave
72
Can sound travel in vacuum?
No
73
What determines sound pitch?
Frequency
74
What determines sound loudness?
Amplitude
75
What determines timbre?
Harmonic content
76
Audible sound frequency range
20 Hz – 20,000 Hz
77
Ultrasound frequency
>20,000 Hz
78
Sound intensity formula
I = P/A
79
Speed of sound highest in
Solids
80
Cooling when sweat evaporates
Evaporation
81
Feeling colder in wind mechanism
Convection
82
Bernoulli equation concept
Higher velocity → lower static pressure
83
Dynamic pressure formula
Pd = ½ρv²
84
Hydrostatic pressure formula
P = ρgh
85
Heart rate formula using ECG
HR = 60 / RR interval
86
Reynolds number formula
Re = ρvd/η
87
Optical power formula
P = 1/f
88
Unit of optical power
Diopter (D)
89
Radiation absorbed dose unit
Gray (Gy)
90
Equivalent dose unit
Sievert (Sv)
91
Function of the cathode in a cathode-ray oscilloscope
Focuses the electron beam onto the screen
92
Function of the anode in a cathode-ray oscilloscope
Accelerates electrons toward the screen
93
Function of horizontal deflection plates
Move electron beam left or right
94
Function of vertical deflection plates
Move electron beam up or down
95
What is half-value thickness?
Thickness that reduces radiation intensity to half of its initial value
96
Constant used in half-value layer calculations
0.693
97
Formula relating half-value thickness and absorption coefficient
μ = 0.693 / d½
98
When absorber thickness increases what happens to transmitted intensity?
Decreases exponentially
99
What happens to light when moving from lower refractive index to higher index?
Bends toward the normal
100
What happens to light when moving from higher refractive index to lower index?
Bends away from the normal
101
Critical angle definition
Angle of incidence above which total internal reflection occurs
102
Condition for total internal reflection
Light moves from higher refractive index to lower refractive index
103
Optical power of a lens formula
P = 1/f
104
Unit of optical power
Diopter (D)
105
If focal length = 0.5 m what is optical power?
2 D
106
Speed of light relationship with refractive index
v = c / n
107
Refractive index meaning
Ratio of light speed in vacuum to speed in medium
108
Equivalent radiation dose formula
H = D × Q
109
Radiation weighting factor meaning
Relative biological effectiveness of radiation
110
Example weighting factor for alpha particles
20
111
What does LET measure?
Energy deposited per unit distance in tissue
112
Why high LET radiation is more damaging
Deposits energy densely in tissues
113
Definition of Bremsstrahlung radiation
X-rays produced when fast electrons decelerate near nuclei
114
Result of Compton scattering
Photon loses energy and changes direction
115
Result of photoelectric effect
Photon ejects electron from atom completely
116
What distinguishes isotopes
Same number of protons but different neutrons
117
What happens in beta minus decay
Neutron converts into proton and electron
118
Effective half-life formula
1/Te = 1/Tphysical + 1/Tbiological
119
If physical and biological half-life are equal what happens to effective half-life
It becomes half the value
120
Definition of linear energy transfer (LET)
Energy deposited per unit path length by radiation
121
Unit of LET
keV/µm
122
What is non-ionizing radiation
Radiation that excites molecules without removing electrons
123
Main biological effect of non-ionizing radiation
Heating of tissues
124
Definition of sound wave
Mechanical vibration that propagates through a medium
125
Sound propagation requires
A material medium
126
Compressions in sound waves
Regions of high pressure
127
Rarefactions in sound waves
Regions of low pressure
128
Pitch of sound depends on
Frequency
129
Loudness depends on
Amplitude
130
Timbre depends on
Harmonic content of the sound wave
131
Sound intensity formula
I = P/A
132
Infrasound frequency range
Below 20 Hz
133
Ultrasound frequency range
Above 20,000 Hz
134
Why ultrasound is used in medicine
High frequency allows detailed imaging
135
Primary cooling mechanism of sweating
Evaporation
136
Why wind makes you feel colder
Convection removes warm air layer
137
Conduction heat transfer definition
Heat transfer through direct contact
138
Convection heat transfer definition
Heat transfer by movement of
Biophysics
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