Quantum and Nuclear Physics (topic 7 & 12)

Question 1

The Photoelectric Effect

Answer 1

Refers to the emission of electrons from a metal surface as a result of the absorption of electromagnetic wave energy. Shows how light (usually thought of as a wave) can exhibit particle-like behavior.

Question 2

Davisson-Germer Experiment

Answer 2

Electrons were scattered from atoms and these scattered electrons produced an interference pattern just like waves.

Question 3

Thomas Young’s Double Slit Experiment

Answer 3

Shows wave behavior of light

Question 4

Electron Diffraction

Answer 4

Shows how electrons (usually thought of as particles) can exhibit wavelike behavior (diffraction and interference).

Question 5

Beta Decay

Answer 5

Is a process by which a nucleus emits an electron or positron. It does not showcase any wave-particle duality.

Question 6

Bohr’s Model for the Hydrogen Atom

Answer 6

The angular momentum of the electron is quantized having values that are multiples of h/2π

Question 7

Photon Energy Equation (E)

Answer 7

E = hf or λ = hc / E

where
E = photon energy (eV or J)
h = Planck’s constant
f = frequency (Hz)
c = speed of light
λ = wavelength (electromagnetic wave)

E is proportional to its frequency

Question 8

Work Function Equation (phi)

Answer 8

φ = h f0

where
φ = Work function (phi)
h = Planck’s constant
f0 = threshold frequency (f0)

Question 9

The De Broglie Hypothesis

Answer 9

Suggests that all matter exhibits wave-like properties. In particular, the momentum of a particle is related to its wavelength where the De Broglie wavelength may be deduced by the following formula:

p = h/λ -> λ = h/p -> λ = h/mv

where
p = momentum
h = Planck’s constant
λ = wavelength
m = mass
v = velocity.

Question 10

Wave-Particle duality

Answer 10

refers to matter acting as both waves and particles.

Question 11

Quantum

Answer 11

Refers to the smallest discrete amount of something.

Question 12

Photon

Answer 12

Is a quantum of electromagnetic radiation (light). Exhibit wave properties under refraction or interference. Exhibit wave properties under its emission or absorption.

Question 13

Angular Momentum Equation

Answer 13

mvr = nh / 2π

where
m = mass of electron,
v = speed of electron,
r = radius of orbit,
n = interger,
h = Planck’s constant.

Question 14

Schrödinger model of the atom

Answer 14

P(r) = |φ|^2 multiplied by Δv

where
P(r) = probability of finding an electron in a small volume,
|φ|^2 = amplitude of wave function squared,
Δv = small volume.

Question 15

Heisenberg’s Uncertainty Principle

Answer 15

The act of observing (making a measurement) alters the system.

Question 16

Heisenberg’s Uncertainty Equation

Answer 16

Δx multiplied by Δp is greater than or equal to h / 4π

OR

ΔE multiplied by Δt is greater than or equal to h / 4π

where
Δx = uncertainty on position,
Δp = uncertainty on momentum,
ΔE = uncertainty on energy,
Δt = uncertainty on time,
h = Planck’s constant

Question 17

Nuclear Radius Equation

Answer 17

R = R0 multiplied by A^1/3

where
R = nuclear radius (m),
R0 = Fermi radius constant,
A = atomic mass number

Question 18

What happens when Alpha decay occurs

Answer 18

Add Helium 4

Question 19

What happens when Beta decay occurs

Answer 19

Add a Beta minus (electron) + anti-electron neutrino

OR

a Beta plus (positron) + electron neutrino

Question 20

Decay Equation

Answer 20

N = N0 multiplied by e ^ -λ t

where
N = final mass (or activity),
N0 = initial mass (or activity),
t = time elapsed,
λ = decay constant = probability of decay at a certain time.

Question 21

Decays / Seconds unit

Answer 21

Becquerel

Question 22

Half-life Equation

Answer 22

T1/2 = ln2/λ

where
T1/2 = half-life of exponential decay,
ln = natural log.

Question 23

Element notation

Answer 23

Number on top of the molecule = mass # (number of nucleons) n + p
Number at the bottom of the molecule = atomic # (# of protons)

Question 24

Isotopes

Answer 24

Same atomic number, different mass number

Question 25

Energy levels

Answer 25

Electrons get excited, go up in energy level. When they go back down, they emit a photon (light) with energy

Energy is quantized - only comes in multiples of h

Question 26

Energy levels (wavelengths and frequencies)

Answer 26

Smallest λ -> highest f and largest E

Question 27

Two types of Beta decay

Answer 27

1. Electron-beta decay
2. Positron-beta decay

Question 28

Gamma decay

Answer 28

γ = photon

**no charge

Question 29

Exponential decay

Answer 29

As parent particles lessen, daughter particles increase

Question 30

Binding energy

Answer 30

The energy released when a nucleus is assembled from its constituent parts. Every time a new element is made, there’s an energy that’s released.

Mass of left hand side ≠ mass of right hand side

Question 31

Einstein’s famous equation

Answer 31

ΔE = Δm c^2

where
ΔE = binding energy (eV or J)
Δm = mass defect (kg or u or (MeV) / c^2)
c = speed of light = 3 x 10^8 m s^-1

Question 32

6 types of quarks (every particle also has an anti-particle)

Answer 32

1. Up
2. Charm
3. Top
4. Down
5. Strange
6. Bottom

Question 33

Hadron

Answer 33

Particle made of quarks
ex. Baryon, Meson

Question 34

Baryon

Answer 34

Particle made of three quarks

Question 35

Meson

Answer 35

Particle made of two quarks (one quark + one anti-quark)

Question 36

Leptons

Answer 36

Other than quarks, there are other fundamental particles called leptons

Question 37

6 types of leptons (every particle also has an anti-particle)

Answer 37

1. τ- = tau
2. µ- = mu
3. e- = electron
4. ντ = tau-neutrino
5. νµ = mu-neutrino
6. νe = electron-neutrino

Question 38

Conservation

Answer 38

The idea that properties must be conserved (same before as after)

Question 39

Higgs boson

Answer 39

Responsible (through interactions) for mass

Question 40

4 main bosons

Answer 40

1. g = gluon
2. W+, W- = W-boson
3. Z° = Z-boson
4. γ = photon

Question 41

Strength of fundamental forces

Answer 41

Gravitational < Weak nuclear < Electromagnetic < Strong nuclear

Question 42

Band of stability in nuclei

Answer 42

1. The darker the points, the more stable
2. Nuclei further from the dark region are increasingly unstable and will quickly decay back into a more stable form
3. Band of stability lies above the one to one ratio of protons and neutrons
4. the stability of nuclei depends on the attractive and repulsive force
5. the band of stability implies that the strong nuclear force must be very short-ranged in nature