1
Q
X Ray Production (5)
A
- electrons emitted from a filament heater (heated by an electric current)
- the high p.d. accelerates the electrons between the filament heater (cathode) and the anode (metal with high m.p.)
- if the electrons have enough energy, when they hit the anode, some x ray photons will be emitted
- due to the electron interacting with the electric field around the nucleus
- the energy of the photon is equal to the Ek lost by the electron when decelerating rapidly by smashing into the anode
2
Q
Features of the X Ray Production Process (4)
A
- happens in a vacuum: electrons would lose energy when colliding with gas molecules
- anode is shaped: x rays come off in desired directions
- tube surrounded by lead shielding: precent exposure to radiation
- anode cooled by oil flowing through it: Ek of electron transferred as heat to anode
3
Q
X Ray Production: Energy of Photons (5)
A
- photons can have less then the max energy, so photons have a distribution of energies
- spikes at specific photon energies
- caused by accelerated electron knocking an orbiting electron out of an energy level
- another electron from a higher level moves to occupy the vacancy
- this releases an x ray photon of wavelength corresponding to the difference in energy levels
4
Q
The intensity of x rays emitted is
A
directly proportional to the number of electrons emitted per second from the filament heater
5
Q
Interaction of X Rays with Matter (4)
A
Simple Scattering
- interacts with orbiting electron
- photon scattered: no change in energy or photon absorption
The Photoelectric Effect
- interacts with orbiting electron
- photoelectron emitted with max Ek, photon no longer exists
Compton Scattering
- interacts with orbiting electron
- electron emitted at high speed, photon continues with less energy and lower frequency
Pair Production
- interacts with nucleus
- electron and positron produced, photon no longer exists
6
Q
X rays are ionising and the electrons produced
A
can cause further ionisations
7
Q
Attenuation (definition)
A
the exponential decrease in intensity
8
Q
Collimated (definition)
A
Beams are travelling in parallel lines
9
Q
Intensity of collimated X Rays (2)
A
- hardly changes with distance when not interacting with different materials
- decreases with distance when passing through a substance
10
Q
A higher attenuation coefficient means
A
it is better at stopping x rays
11
Q
A Contract Material is and is used for …
A
- a material with a high attenuation coefficient (barium/iodine)
- to see detail of different types of soft tissues with similar attenuation coefficients
12
Q
CAT Scans can (3)
A
- provide very accurate pictures of the position of internal organs without being obscured by other structures in the body
- show soft tissues clearly
- produce 3D images
13
Q
Production of a CAT Scan Image (6)
A
- a thin fan shaped x ray beam is passed though patient
- beam detected by a ring of detectors
- x ray source is rotated around patient
- source and detectors move up about a cm
- next revolution looks at next slice of body
- computer processes data to produce 3D image
A Level Physics
flashcards
Decks in class (79)
# Cards
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GCSE Equations - All34
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Module 1 - 1.1.1 Planning2
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Module 1 - 1.1.2 Implementing1
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Module 1 - 1.1.3 Analysing3
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Module 1 - 1.1.4 Evaluation1
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Module 2 - 2.1.1 Physical Quantities2
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Module 2 - 2.1.2 SI Units9
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Module 2 - 2.2.1 Measurements and Uncertainties9
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Module 2 - 2.3.1 Nature of Quantities2
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Module 3 - 3.1.1 Kinematics7
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Module 3 - 3.1.2 Linear Motion7
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Module 3 - 3.1.3 Projectile Motion1
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Module 3 - 3.2.1 Dynamics6
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Module 3 - 3.2.2 Motion with Non-Uniform Acceleration3
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Module 3 - 3.2.3 Equilibrium10
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Module 3 - 3.2.4 Density and Pressure6
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Module 3 - 3.3.1 Work and Conservation of Energy5
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Module 3 - 3.3.2 Kinetic and Potential Energies1
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Module 3 - 3.3.3 Power1
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Module 3 - 3.4.1 Springs11
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Module 3 - 3.4.2 Mechanical Properties of Matter11
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Module 3 - 3.5.1 Newton's Laws of Motion6
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Module 3 - 3.5.2 Collisions4
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Module 4 - 4.1.1 Charge7
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Module 4 - 4.1.2 Mean Drift Velocity10
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Module 4 - 4.2.2 E.m.f. and P.d.8
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Module 4 - 4.2.3 Resistance6
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Module 4 - 4.2.4 Resistivity6
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Module 4 - 4.2.5 Power3
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Module 4 - 4.3.1 Series and Parallel Circuits2
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Module 4 - 4.3.2 Internal Resistance6
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Module 4 - 4.3.3. Potential Dividers1
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Module 4 - 4.4.1 Wave Motion20
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Module 4 - 4.4.2 Electromagnetic Waves11
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Module 4 - 4.4.3 Superposition9
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Module 4 - 4.4.4 Stationary Waves8
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Module 4 - 4.5.1 Photons3
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Module 4 - 4.5.2 The Photoelectric Effect8
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Module 4 - 4.5.3 Wave-Particle Duality1
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Mock Revision - ignore49
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Astrophysics - ignore37
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Module 5 - 5.1.1 Temperature9
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Module 5 - 5.1.2 Solid, Liquid and Gas14
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Module 5 - 5.1.3 Thermal Properties of Materials3
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Module 5 - 5.1.4 Ideal Gases11
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Module 5 - 5.2.1 Kinematics of Circular Motion3
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Module 5 - 5.2.2 Centripetal Force7
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Module 5 - 5.3.1 Simple Harmonic Oscillations6
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Module 5 - 5.3.2 Energy of a Simple Harmonic Oscillator2
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Module 5 - 5.3.3 Damping14
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Module 5 - 5.4.1 Point and Spherical Masses5
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Module 5 - 5.4.2 Newton's Law of Gravitation1
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Module 5 - 5.4.3 Planetary Motion5
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Module 5 - 5.4.4 Gravitational Potential and Energy9
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Module 5 - 5.5.1 Stars24
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Module 5 - 5.5.2 Electromagnetic Radiation From Stars30
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Module 5 - 5.5.3 Cosmology31
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Module 5 - Detailed Sections of Astrophysics17
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Module 6 - 6.1.1 Capacitors9
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Module 6 - 6.1.2 Energy5
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Module 6 - 6.1.3 Charging and Discharging Capacitors9
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Module 6 - 6.2.1 Point Spherical Charges4
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Module 6 - 6.2.2 Coulomb's Law4
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Module 6 - 6.2.3 Uniform Electric Field2
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Module 6 - 6.2.4 Electrical Potential and Energy8
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Module 6 - 6.3.1 Magnetic Fields16
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Module 6 - 6.3.2 Motion Of Charged Particles8
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Module 6 - 6.3.3 Electromagnetism19
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Module 6 - 6.4.1 The Nuclear Atom12
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Module 6 - 6.4.2 Fundamental Particles14
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Module 6 - 6.4.3 Radioactivity17
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Module 6 - 6.4.4 Nuclear Fission and Fusion15
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Module 6 - 6.5.1 Using X-Rays13
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Module 6 - 6.5.2 Diagnostic Methods in Medicine8
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Module 6 - 6.5.3 Using Ultrasound18
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Module 3 Practicals8
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Module 4 Practicals15
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Module 5 Practicals10
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Module 6 Practicals9
