Particles and Medical Physics Flashcards

1
Q

What is Capacitance and its equation?

A

Capacitance is defined as the charge stored per unit potential difference across it.
= charge
Potential difference

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2
Q

Two or more capacitors in series rules

A

Capacitance = 1 = 1 + 1
C C1 C2
Charge stored by each capacitor is the same
Potential difference = V= V1 + V2

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3
Q

Two or more capacitors in parallel

A

Capacitance= C= C1 + C2
The potential difference across each is the same
Charge Q= Q1 +Q2

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4
Q

What is the area under a p.d. Charge graph

A

Energy stored

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5
Q

Energy stored by capacitor 3 equations

A

W=0.5 x QV

W= 0.5 x Q^2
C

W= 0.5 xV^2 xC

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6
Q

What is Exponential decay

A

Exponential decay is a constant-ratio process in which a quantity decreases by the same factor in equal time intervals

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7
Q

What is electric field strength

A

Electric field strength is the force experienced per unit positive charge at that point

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8
Q

Electric field strength equation

A

E=F
Q

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9
Q

Coulomb’s law

A

Any two point charges exert an electrostatic (electrical) force on each other that is directly proportional to the product of their charges and inversely proportional to the square of their separation.

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10
Q

electrostatic force equation for the force between two point charges

A

F= Qq
4πε0r^2

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11
Q

What is the value of epsilon-nought ε0

A

8.85x10^-12

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12
Q

X-ray

A

This is a short wavelength and high frequency electromagnetic wave (10^-8m to 10^-13m), which can be used in medical imaging

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13
Q

Thermionic emission

A

This is the emission of electrons from the surface of a heated piece of metal or a hot metal wire

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14
Q

Attenuation

A

This is the decrease in the intensity of electromagnetic radiation as it passes through matter and /or space. Bone attenuates x-rays more than soft tissues

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15
Q

Simple Scatter description

A

The x-ray photon is scattered elastically by an electron 1-20 keV

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16
Q

Photoelectric effect

A

The x-ray photon disappears and removes an electron from the atom. <100keV

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17
Q

Compton effect

A

The x-ray photon is scattered by an electron, it’s energy is reduced, and the electron is ejected from the atom. 0.5-5.0 MeV

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18
Q

Pair production

A

The x-ray photon disappears to produce an electron-positron pair >1.02MeV

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19
Q

Basic structure of an X-ray tube components

A

Heater (cathode), target metal (anode), high voltage power supply,

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20
Q

What is a medical tracer

A

This is a radiopharmaceutical that is a compound labelled with a radioisotope that can be traced inside the body using a gamma camera

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21
Q

Ultrasound

A

This is a longitudinal wave with frequency greater than 20kHz

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22
Q

Ultrasound transducer

A

This is a device that emits and receives ultrasound

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23
Q

Piezoelectric effect

A

The production of an electromotive force by some crystals, such as quartz, when they are compressed stretched, twisted or distorted

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24
Q

Acoustic independence

A

This is defined as the product of the density of a substance and the speed of ultrasound in that substance

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25
Magnetic field
This is a field surrounding a permanent magnet or a current-carrying conductor in which magnetic objects experience a force.
26
Magnetic flux density B (Tesla T)
The strength of a magnetic field.
27
Magnetic flux (Wb)
This is the product of the component of the magnetic flux density perpendicular to a given area and that cross sectional area. BAcosθ
28
Magnetic flux linkage
This is the product of the number of turns in a coil N and the magnetic flux φ
29
Faradays law of electromagnetic induction
The magnitude of the induced e.m.f is directly proportional to the rate of change of magnetic flux linkage
30
Lenz's law
The direction of the induced e.m.f or current is always such as to oppose the change producing it
31
Fleming's left hand rule
This is used to determine the direction of the force experienced by a current carrying conductor placed perpendicular to the external magnetic field. First finger- external magnet field, second finger- conventional current, thumb motion(force) of the wire.
32
Alpha Particle Scattering experiment explain and 2 observations and conclusions
Narrow beam of alpha particles fired at a thin piece of gold foil. 1. Most of the alpha particles passed straight through with no scattering- most of the atom is empty space and mass is concentrated in nucleus. 2. Very few of the alpha particles were deflected through angles of more than 90 degrees - the nucleus has a positive charge because it repelled the few alpha particles that came near it.
33
Nucleon number
(Mass number) is the total number of protons and neutrons in a nucleus
34
Proton number
(Atomic number) is the total number of protons in a nucleus
35
Isotopes
These are nuclei of the same element that have the same number of protons but different numbers of neutrons
36
Nucleon
This is a particle in the nucleus of an atom, either a proton or neutron
37
Antiparticle
This is the antimatter counter part of a particle with the opposite charge to the particle (if it has charge) and exactly the same rest mass as the particle
38
Electron antiparticle
Positron
39
Proton antiparticle
Antiproton
40
Neutron antiparticle
antineutron
41
Neutrino antiparticle
Antineutrino
42
4 fundamental forces
Strong nuclear, weak nuclear, electromagnetic, gravitational
43
Fundamental particle
This is a particle that has no internal structure and hence cannot be split into smaller particles
44
Quark
A quark is an elementary particle that can exist in 6 forms ( plus their antiparticles) and joins with other quarks to make up hadrons
45
baryon
Any hadron made with a combination of 3 quarks
46
Meson
Any hadron compromising a combination of a quark and an anti-quark
47
Hadron
A hadron is a particle or antiparticle that is affected by the strong nuclear force and, if charged, by the electromagnetic force.
48
Lepton
This is a fundamental particle or antiparticle that is not affected by the strong nuclear force
49
Neutrino
A neutrino is a lepton that carries no charge and may have a tiny mass, less than a millionth the mass of an electron
50
Beta-minus β- decay
A neutron in an unstable nucleus decays into a proton, electron and an electron antineutrino
51
beta - plus β+ decay
A proton decays into a neutron, positron and an electron neutrino
52
Radioactive decay
This is the process by which an unstable atomic nucleus emits energy by radiation and its nature is spontaneous and random
53
Parent nucleus
The nucleus before decay
54
Daughter nucleus
The nucleus after the decay
55
Radioactive decay is random because
We cannot predict when a particular nucleus in a sample will decay or which one will decay next and each nucleus within a sample has the same chance of denying per unit time
56
Radioactive decay is spontaneous because
The decay of nuclei is not affected by the presence of other nuclei in the sample and external factors such as pressure
57
Half life
The half life of an isotope is the average time it takes for half the number of active nuclei in the sample to decay
58
Activity
This is the rate at which nuclei decay or disintegrate in a radioactive source. It is also the number of alpha, beta or gamma photons emitted from the source per unit time
59
Decay constant
The decay constant of an isotope is the probability of decay of an individual nucleus per unit time
60
Strong nuclear force
Acts between all nucleons. Has a very short range. The force is attractive to about 3fm and repulsive below 0.5fm.