paper 2 Flashcards
memorise
What is the relationship between intensity (I), power (P), and area (A) for a wave?
I = P / A
What is the relationship between the wavelength (λ), slit separation (a), and fringe spacing (x) in Young’s double-slit experiment?
λ = (a * x) / D
where D is the distance to the screen.
What is the critical angle (C) in total internal reflection?
sin C = 1 / n
where n is the refractive index.
What is the relationship between the refractive index (n), speed of light in a vacuum (c), and speed of light in a medium (v)?
n = c / v
What is the relationship between the angle of incidence (θ1) and the angle of refraction (θ2) in Snell’s law?
n1 * sin θ1 = n2 * sin θ2
What is the principle of superposition?
When two waves meet, the resultant displacement is the sum of the individual displacements.
What is the difference between constructive and destructive interference?
Constructive interference increases amplitude (in phase), while destructive interference decreases amplitude (out of phase).
What is a stationary wave?
A wave formed by the superposition of two waves with the same frequency traveling in opposite directions.
What is the relationship between the frequency (f) and period (T) of a wave?
f = 1 / T
What is the relationship between the speed of light (c), frequency (f), and wavelength (λ)?
c = f * λ
What is the work function (ϕ) in the photoelectric effect?
The minimum energy required to remove an electron from a metal surface.
What is the threshold frequency (f0) in the photoelectric effect?
The minimum frequency of light required to emit electrons from a metal surface.
What is the equation for the maximum kinetic energy (KEmax) of photoelectrons?
KEmax = hf - ϕ
What is the de Broglie wavelength (λ) of a particle?
λ = h / p
where p is momentum.
What is the relationship between the energy (E) and wavelength (λ) of a photon?
E = h * c / λ
What is the relationship between the energy (E) and frequency (f) of a photon?
E = h * f
What is the significance of electron diffraction?
It demonstrates the wave-like behavior of electrons.
What is the quark composition of a proton?
uud (two up quarks and one down quark).
What is the quark composition of a neutron?
udd (one up quark and two down quarks).
What is beta-minus decay?
A neutron decays into a proton, emitting an electron and an antineutrino.
What is beta-plus decay?
A proton decays into a neutron, emitting a positron and a neutrino.
What is pair production?
A photon converts into a particle-antiparticle pair (e.g., electron and positron).
What is annihilation?
A particle and its antiparticle collide, converting their mass into energy (photons).
What is the conservation of energy in particle interactions?
The total energy before and after an interaction remains constant.
What is the purpose of a CT scan?
To produce detailed 3D images of the body using X-rays.
What is the piezoelectric effect?
The generation of an electric charge in response to mechanical stress, used in ultrasound transducers.
What is the Doppler effect?
The change in frequency of a wave due to the relative motion of the source and observer.
What is the purpose of a gamma camera?
To detect gamma rays emitted by radioactive tracers in the body.
What is the equation for radioactive decay?
N = N0 * e^(-λt)
where N is the remaining quantity, N0 is the initial quantity, λ is the decay constant, and t is time.
What is half-life?
The time taken for half the radioactive nuclei in a sample to decay.
What is the relationship between the intensity (I) of X-rays and the thickness (x) of a material?
I = I0 * e^(-μx)
where μ is the attenuation coefficient.
What is the acoustic impedance (Z) of a material?
Z = ρ * c
where ρ is density and c is the speed of sound.
What is the reflection coefficient for ultrasound waves?
Ir / I0 = ((Z2 - Z1)^2) / ((Z2 + Z1)^2)
What is the Doppler shift equation for ultrasound?
Δf / f = (2v * cos θ) / c
What is the purpose of MRI?
To produce detailed images of the body using strong magnetic fields and radio waves.
What is the principle behind X-ray imaging?
X-rays pass through soft tissue but are absorbed by dense materials like bones, creating contrast in the image.
What is the purpose of a collimator in X-ray imaging?
To narrow the X-ray beam and reduce scatter, improving image clarity.
What is the relationship between X-ray energy and penetration?
Higher-energy X-rays penetrate deeper into tissues, while lower-energy X-rays are absorbed more easily.
What is the role of a scintillator in a gamma camera?
It converts gamma rays into visible light, which is then detected by photomultiplier tubes.
What is the purpose of a photomultiplier tube in a gamma camera?
It amplifies the light signal from the scintillator to produce an electrical signal.
What is the principle behind ultrasound imaging?
High-frequency sound waves are reflected at tissue boundaries, and the echoes are used to create an image.
What is the role of a transducer in ultrasound imaging?
It emits and receives ultrasound waves, converting electrical signals into sound waves and vice versa.
What is the purpose of gel in ultrasound imaging?
It ensures good contact between the transducer and the skin, reducing air gaps that could scatter the sound waves.
What is the principle behind MRI imaging?
Strong magnetic fields and radio waves cause hydrogen nuclei in the body to emit signals, which are used to create detailed images.
What is the role of the gradient coils in an MRI machine?
They create varying magnetic fields to spatially encode the signals from hydrogen nuclei, allowing for 3D imaging.
name and describe the function of a gamma camera ( 5 marks)
collimator/lead tubes gamma follows along axis of lead tubes
scintillator gamma ray produces photons
photomultiplier
electrons produced by photons from visible light
and computer used to generate image
describe and explain the technique of carbon dating
living plants absorb carbon 14
once dead no longer absorbs carbon 14
fraction of carbon 14 in dead and alive is used and then x= x.E^-yt is used rearranged for time
explain the role of fuel rods , control rods and a moderator in a nuclear reactor
fuel rod has uranium / fissile material
control rods absorbs neutrons
moderator , slows down (moderates) the speed of fast moving neutrons
slow moving means higher chance of fission (chain reaction)
describe the principles of PET scan tech
annhilation of from electron and positron
produces to gamma photons
patient is surrounded by gamma photons which is then detected forms 3D image
describe the nature and range of 3 forces acting on protons and neutrons in the nucleus
strong nuclear force
attractive at long distances , and repulsive and short distances
gravitational force
strong attractive and long ranged
electrostatic forces (think of ions) protons repulse and neutrons are “neutral”
