Wave - A disturbance that transfers energy, often through a medium (mechanical waves) although it is not required (non-mechanical waves) eg. sound waves, light waves

Frequency/angular frequency - The rate at which an oscillation occurs, either in hertz or rad/s

Wavelength λ - The distance between the crests of a wave

Amplitude - The maximum displacement of a wave measured from its equilibrium equation

Phase Angle φ - the angular displacement of a wave from a reference point in time

Radian - A unit of measurement used to express angles relative to the radius of a circle. 360* is 2π

Sine and Cosine functions - opp/hyp and adj/hyp. Can be used to model waves by rotating a point along the circumference of a circle and graphing its x and y coordinates relative to the center.

Initial condition - The starting conditions of the wave at t = 0, eg. initial angle, velocity, displacement, etc.

Types of Damping

Critical - Immediately to equilibrium

Light - Still continues to oscillate about equilibrium, but amplitude decays over time until it reaches 0

Heavy - Slowly to equilibrium

What is the complete total energy function for an oscillating mass on a spring system inside a viscous liquid?

What is the complete total energy function for raindrop falling through the atmosphere of a planet?

Certain nodes where there are points of 0 displacement

Certain antinodes where there are points of max displacement

Oscillates only between two defined boundaries

Constructive interference - two waves in phase combine to create a wave with greater amplitude

Constructive interference - two waves out of phase combine to create a wave with lower amplitude

How do standing waves form?

Reflection at the boundaries, then constructive and destructive interference forms nodes and antinodes for specific frequencies

How does changing the strobe light frequency affect the apparent motion of a standing wave on a vibrating string?

How does changing the diameter of the measuring cylinder affect the resonance length for a given tuning fork frequency?

What equipment did you find most interesting today? Why?

The tuning fork is the most interesting. Metals vibrate at frequencies, that is common knowledge but its uses and applications in experiments I'm not sure about, which is why it's interesting.

What was one thing you found confusing or surprising?

What standing wave related experiments could be conducted with a laser pointer? I struggle to think of a situation where a laser pointer could relate to standing waves.

Which of your personal research questions would you most like to test? Why?

I want to do the stroboscope research question, but mostly because I just want to see flashing lights and the way you described the visuals made me curious.

Rays are straight lines that shows average direction of movement, perpendicular to the ray, showing the peaks/crests of waves.

Angle of Incidence - The angle between the normal and the ray that strikes the object

Angle of reflection - The angle between the reflected ray and the normal

Angle of incidence = Angle of reflection

Energy determines colour, given by the equation E = hf

When an object passes across a boundary, it can be reflected or refracted. For both of these, the frequency does not change but its wavelength does, therefore colour does not change.

The light comes from excited electrons in atoms that releases photons when it increases and then eventually drops an energy level.

How can the colour of the laser be changed?

The colour of a laser can change when it gains energy.

The surface of diffraction grates contain many tiny grooves. When a ray of white light diffracts on the grooves, the different wavelengths diffract in different angles, separating the light into multiple colours. When a ray of a single wavelength (single colour) diffracts on the grooves, it shows the areas of constructive and destructive interference instead.

maximum when sinθ = 1

nmax = d/λ

maxima = 2nmax + 1 (central maxima)

Dark fringes in between two principal maxima = N-1

Bright fringes in between two principal maxima = N-2

so depending on the number of slits, there will be greater number of secondary maxima

sintheta = nλ/b = nλ/d

wavelength is same fo rboth

λ/b - λ/d

This means that objects moving away will look red and objects that are moving closer will look blue.

Similarly, the pitch of sound moving away will be low and moving closer will be high

HOWEVER if the object is stationary and the observer is moving, the wavelength does not change, the frequency still does

Only consider the component of the relative velocity that is parallel to the line of sight

For an object moving in a circle, the relative velocity will be changing as it goes through a revolution

R0 is a constant 1.2x10^-15, radius of one proton or neutron (fermi radius)

A = Nucleon number

DENSITY ALWAYS REMAINS THE SAME

Density vs nucleon number graph is FLAT

E = hf

lambda = c/f

lambda = h/mv

mvr = nh/2pi

r = n^2a0

en = -ke^2/2rn

Q can be energy

k is conductivity

A is area

ΔX is usually length of the segment

When two objects are in contact and insulated ΔQ/Δt are equal for both, so you can solve

e is emmisivity

σ is Stefan-Boltzmann consant, 5.67E-8

A is area

T is temperature, in K

(ii) Use error propagation (in data booklet)

(iii) calculate the uncertainty in repeated measurements.

b (brightness) = L (luminosity)/4pid^2 (distance from object)

E is energy absorbed by the object, it can be from a source of power, gravitational potential energy, etc.

Egpe = mgh, so

snmgL = nmcΔT

sgL = cΔT

Isolating heat capacity,

c = sgL/ΔT

c = Q(J)/m(kg)ΔT(K), units are Jkg^-1K^-1

Materials have specific latent heat, the amount of energy required to change state (Lvapourisation, Lfusion)

Calculate power from change in temperature over time, then calculate Q during only freezing from power, then use Q = mL

Albedo (reflectiveness) - scattered power/incident power

solar constant x cross sectional area of earth x (1-albedo) = eσAT^4

where eσAT^4 is with or without the atmosphere

Incoming Intensity is 100W, with an albedo of 0.3, giving 30W of reflected energy.

The remainder is absorbed and then reflected again, 70W + 60W = 130W

Planets need atmospheres to retain heat otherwise they end up extremely cold, like Mars, or if they have thick atmospheres they get extremely hot like Venus

As it is insulated, both bodies will eventually reach the same temperature

Just trace the charge, it splits at the node

Current will be the same through the circuit, so it must be the same before and after

Ideal ammeter has 0 resistance

Remove outliers and do extra trials (and don't forget to justify)

1. when linearized, the graph creates a straight trendline

2. if there is no constant, then the graph should pass through the origin

3. calculating the slope should give you the value of a constant (and be the same at all points)

And also use powers in calculator, because it's easy and costs you nothing to be 100% sure

Regression lines are ALWAYS linear

Trendlines can be exponential, logarithmic, etc etc

IF THE TRENDLINE IS NONLINEAR AND YOU ADD A REGLINE YOU ARE MAKING A BIG MISTAKE

E in MeV

m in u

m = E/c^2

m = MeVc^-2

REMEMBER THAT IF YOU WANT TO START WORKING WITH KG AND J YOU NEED TO CONVERT

u = 1.66E-27kg

eV = 1.60E-19J

Δm is mass defect

Δm = (Z*mp + (A-Z)mn) - matom

INFO WILL ALWAYS BE PROVIDED

BE eats some of the mass, which is hwy when BE is broken, atoms get more mass

Why do heavier nuclei need more neutrons than protons to be stable?

D. Neutrons add to the strong nuclear binding without increasing repulsive forces, since they are neutral. In heavier nuclei, more neutrons are needed to overcome the growing proton-proton repulsion and to help bind the nucleus together.

Why does proton repulsion become a bigger problem in larger nuclei?

B. As the number of protons increases, the repulsive electrostatic (Coulomb) force between them grows stronger. Since this force acts over long ranges and the protons are all positively charged, the total repulsion becomes more significant in larger nuclei.

Why are nuclei with too many or too few neutrons unstable?

C. If the neutron-to-proton ratio is too high or too low, the balance of nuclear forces is disrupted. The nucleus becomes energetically unstable and may undergo beta decay to adjust the ratio and reach a more stable configuration.

Why can’t the strong nuclear force always prevent decay?

A. The strong nuclear force only acts over very short distances (on the order of femtometers). In large nuclei, many protons are too far apart for the strong force to hold them all together effectively, which limits the ability of the force to prevent decay.

• When mass A is too large (heavy elements)

• Emits a 2p/2n particle

Beta decay

• When ratio of neutrons to protons is too large

• Neutron changes into a proton

• Neutrino released

• B- is high energy electron

• B+ is a positron (anti electron)

Gamma decay

• When need to release a little bit more energy

V with a line is an anti neutrino

NEVER have two antiparticles

only ever have 1 real and 1 anti

Work done on the gas W = -PdeltaV

deltaU = W + Q

where W depends on whether it is done by or on the gas.

for change in pressure AND volume,

deltaU = delta(PV) + Q

(PV has to be non zero)

for change in volume only,

deltaU = PdeltaV + Q

Isothermal vs Adiabatic

Isothermal is when no change in T (P proportional 1/V, or deltaPV=0)

Adiabatic is really fast with no change Q (with a smaller change in V)

(Clausius form)

It is impossible in a cyclical process to completely convert heat into mechanical work

(Kevin Planck)