paper 2

Question 1

What is the relationship between intensity (I), power (P), and area (A) for a wave?

Answer 1

I = P / A

Question 2

What is the relationship between the wavelength (λ), slit separation (a), and fringe spacing (x) in Young’s double-slit experiment?

Answer 2

λ = (a * x) / D

where D is the distance to the screen.

Question 3

What is the critical angle (C) in total internal reflection?

Answer 3

sin C = 1 / n

where n is the refractive index.

Question 4

What is the relationship between the refractive index (n), speed of light in a vacuum (c), and speed of light in a medium (v)?

Answer 4

n = c / v

Question 5

What is the relationship between the angle of incidence (θ1) and the angle of refraction (θ2) in Snell’s law?

Answer 5

n1 * sin θ1 = n2 * sin θ2

Question 6

What is the principle of superposition?

Answer 6

When two waves meet, the resultant displacement is the sum of the individual displacements.

Question 7

What is the difference between constructive and destructive interference?

Answer 7

Constructive interference increases amplitude (in phase), while destructive interference decreases amplitude (out of phase).

Question 8

What is a stationary wave?

Answer 8

A wave formed by the superposition of two waves with the same frequency traveling in opposite directions.

Question 9

What is the relationship between the frequency (f) and period (T) of a wave?

Answer 9

f = 1 / T

Question 10

What is the relationship between the speed of light (c), frequency (f), and wavelength (λ)?

Answer 10

c = f * λ

Question 11

What is the work function (ϕ) in the photoelectric effect?

Answer 11

The minimum energy required to remove an electron from a metal surface.

Question 12

What is the threshold frequency (f0) in the photoelectric effect?

Answer 12

The minimum frequency of light required to emit electrons from a metal surface.

Question 13

What is the equation for the maximum kinetic energy (KEmax) of photoelectrons?

Answer 13

KEmax = hf - ϕ

Question 14

What is the de Broglie wavelength (λ) of a particle?

Answer 14

λ = h / p

where p is momentum.

Question 15

What is the relationship between the energy (E) and wavelength (λ) of a photon?

Answer 15

E = h * c / λ

Question 16

What is the relationship between the energy (E) and frequency (f) of a photon?

Answer 16

E = h * f

Question 17

What is the significance of electron diffraction?

Answer 17

It demonstrates the wave-like behavior of electrons.

Question 18

What is the quark composition of a proton?

Answer 18

uud (two up quarks and one down quark).

Question 19

What is the quark composition of a neutron?

Answer 19

udd (one up quark and two down quarks).

Question 20

What is beta-minus decay?

Answer 20

A neutron decays into a proton, emitting an electron and an antineutrino.

Question 21

What is beta-plus decay?

Answer 21

A proton decays into a neutron, emitting a positron and a neutrino.

Question 22

What is pair production?

Answer 22

A photon converts into a particle-antiparticle pair (e.g., electron and positron).

Question 23

What is annihilation?

Answer 23

A particle and its antiparticle collide, converting their mass into energy (photons).

Question 24

What is the conservation of energy in particle interactions?

Answer 24

The total energy before and after an interaction remains constant.

Question 25

What is the purpose of a CT scan?

Answer 25

To produce detailed 3D images of the body using X-rays.

Question 26

What is the piezoelectric effect?

Answer 26

The generation of an electric charge in response to mechanical stress, used in ultrasound transducers.

Question 27

What is the Doppler effect?

Answer 27

The change in frequency of a wave due to the relative motion of the source and observer.

Question 28

What is the purpose of a gamma camera?

Answer 28

To detect gamma rays emitted by radioactive tracers in the body.

Question 29

What is the equation for radioactive decay?

Answer 29

N = N0 * e^(-λt) ## Footnote where N is the remaining quantity, N0 is the initial quantity, λ is the decay constant, and t is time.

Question 30

What is half-life?

Answer 30

The time taken for half the radioactive nuclei in a sample to decay.

Question 31

What is the relationship between the intensity (I) of X-rays and the thickness (x) of a material?

Answer 31

I = I0 * e^(-μx) ## Footnote where μ is the attenuation coefficient.

Question 32

What is the acoustic impedance (Z) of a material?

Answer 32

Z = ρ * c ## Footnote where ρ is density and c is the speed of sound.

Question 33

What is the reflection coefficient for ultrasound waves?

Answer 33

Ir / I0 = ((Z2 - Z1)^2) / ((Z2 + Z1)^2)

Question 34

What is the Doppler shift equation for ultrasound?

Answer 34

Δf / f = (2v * cos θ) / c

Question 35

What is the purpose of MRI?

Answer 35

To produce detailed images of the body using strong magnetic fields and radio waves.

Question 36

What is the principle behind X-ray imaging?

Answer 36

X-rays pass through soft tissue but are absorbed by dense materials like bones, creating contrast in the image.

Question 37

What is the purpose of a collimator in X-ray imaging?

Answer 37

To narrow the X-ray beam and reduce scatter, improving image clarity.

Question 38

What is the relationship between X-ray energy and penetration?

Answer 38

Higher-energy X-rays penetrate deeper into tissues, while lower-energy X-rays are absorbed more easily.

Question 39

What is the role of a scintillator in a gamma camera?

Answer 39

It converts gamma rays into visible light, which is then detected by photomultiplier tubes.

Question 40

What is the purpose of a photomultiplier tube in a gamma camera?

Answer 40

It amplifies the light signal from the scintillator to produce an electrical signal.

Question 41

What is the principle behind ultrasound imaging?

Answer 41

High-frequency sound waves are reflected at tissue boundaries, and the echoes are used to create an image.

Question 42

What is the role of a transducer in ultrasound imaging?

Answer 42

It emits and receives ultrasound waves, converting electrical signals into sound waves and vice versa.

Question 43

What is the purpose of gel in ultrasound imaging?

Answer 43

It ensures good contact between the transducer and the skin, reducing air gaps that could scatter the sound waves.

Question 44

What is the principle behind MRI imaging?

Answer 44

Strong magnetic fields and radio waves cause hydrogen nuclei in the body to emit signals, which are used to create detailed images.

Question 45

What is the role of the gradient coils in an MRI machine?

Answer 45

They create varying magnetic fields to spatially encode the signals from hydrogen nuclei, allowing for 3D imaging.

Question 46

name and describe the function of a gamma camera ( 5 marks)

Answer 46

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

Question 47

describe and explain the technique of carbon dating

Answer 47

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

Question 48

explain the role of fuel rods , control rods and a moderator in a nuclear reactor

Answer 48

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)

Question 49

describe the principles of PET scan tech

Answer 49

annhilation of from electron and positron produces to gamma photons patient is surrounded by gamma photons which is then detected forms 3D image

Question 50

describe the nature and range of 3 forces acting on protons and neutrons in the nucleus

Answer 50

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"