Module 5 Flashcards
Define temperature
How hot an object is
Define thermal equalibrium
No net flow of thermal energy
Define internal energy
The sum of the randomly distrubuted kinetic and potential energies of atoms or molecules within the substance
What happens during the melting or boiling point of a substance
Electrostatic potenial energy increases
Internal energy increases
Temperature stays the same
Define specific heat capacity
Energy required per unit mass to change the temparature by 1K
Circuit uncluded in specific heat capacity
Power supply
Switch
Variable resistor
Heater (voltmeter in parralel)
Ammeter
Define spacific latent heat
The amount of energy required to change the phase per unit mass while at constant tamperature
Solid to liquid energy
Specific latent heat of fusion
Liquid to gas energy
Spacific latent heat of vapourisation
Boyles law
p1V1=p2V2
Combined gas law
p1V1/T1 = p2V2/T2
How to find angle in radians
Arc length/Radius
Define centripital acceleration
Force that acts towards the centre of a circle
Equation for V in circular motion
V=2pir/T
EQ for Vmax in oscillations
V=2piFA
or V=wA
Define free oscillation
Allowed to osciallate without any external forces
Also known as natural frequency
Define forced oscillation
Driver force is applied to an oscillator and the object will vibrate at the driving frequency
Define resonance
If the driving frequency is equal to the natural frequency the onject will resonate causing a spike in amplitude
Keplars 1st law
The orbit of a planet is an ellipse with the sun at one of the 2 foci
Keplars 2nd law
A line segment joining a planet and the sun sweeps out equal areas during equal intervals of time
Keplars 3rd law
The square of the orbital period of a planet is directly proportional to the cube of its average distance from the sun
Define gravitational potential
Work done per unit mass to move an object from infinity to a point in a gravitational feild
How does moving from one point in a gravitational feild to another change gravitational potential
Moving away from a point mass increases gravitational potential
Eq for GPE in cosmology
E=mV (v is gravitational potential)
Star sequence for star between 0.5 and 1M0
Nebula
main sequence
red giant
planetary nebula
White dwarf
Star sequence for star greater than 1M0
Nebula
main sequence
red supergiant
supernova
2M core mass=Neutron star
3M core mass=Black hole
What is an excited atom
When an electron moves from a lower to a higher energy level within an atom in a gas
This causes a photon to be emitted of the energy required to transition
Define emmission line spectra
Each element produces a unique emmision line spectrum because of its unique set of energy levels
Define continuous spectra
All visable frequencies or wavelengths are present. The atoms of a heated solid metal will produce this type of spectrum
Define absorbtion line spectra
This type of spectrum has series of dark spectral lines against the background of a continuous spectrum. The dark lines have exactly the same wavelengths as the bright emission spectral lines for the same gas atoms.
How are elements in stars detected
Absorbtion line spectrum
If we know the line spectrum of a particular element
What light is used in a diffraction grating
Monochromatic
Under what circumstances are minima and maxima found
Minima = n x wavelength
Maxima = (n+0.5) wavelength
Define 1 AU
Avr distance from earth to sun
Define parsec
Distance at which a radius of 1 AU subtends an angle of 1 arcsecond
1 arcsecond in degrees
1/3600
When is stellar parralax used to measure distance from the earth to an object
distances less than 100pc
Doppler effect in starlight
If the galaxy is blue shifted it is moving towards the earth
red shifted= moving away
Hubbles law
Galaxies are red shifted so moving away from us
The further away the galaxy is the faster it is moving away
State the cosmological principal
The universe is homogeneous (matter is distributed uniformly) and isotropic (the universe looks the same in all directions / there is no centre or edge to the universe
Evidence for the big bang
Microwave background radiation
The expanding universe
Age of the universe
1/Ho
Name a similarity between molecules in a liquid and a solid at room temp
KEs are the same
Mass required for a white dwarf to form
Under 1.4 MO
Mass required for neutron star to form
2 MO
Mass required for black hole to form
> 3 MO
What happens in red giants
fusion no longer takes place in the core as temp isnt high enough
fusion occurs in the shell around the core
these layers expand and cool
Order of events beginning of the universe
Universe starts to expand
quarks and leptons form
hadrons form
nuclei form
atoms form
How to find pascals from 1AU and arcseconds(d)
1/d
what can be used when answering a Q about root mean square speed or escape velocity
Maxwell boltzmann distribution
What is newtons law of gravitation
The force between two point masses is directly proportional to the product of their masses and inversly proportional to the square of their seperation
Stellar luminosity graphs in relation to temp
Higher temp = higher and to the left
Resonance graph in relation to damping
High damping = lower and to the left
Define luminosity
Total radiant power of a star
