nuclear physics Flashcards
Mass of proton
a proton has a mass almost 2000 times that of the electron
types of quarks
up, down , top, bottom, charm, strange
how to identify anti quarks
they’re is a horizonal on top of the quark symbol
Elementary particle
a particle whose substructure is unknown.
Water molecules are they elementary particles
NO
Water molecules we know are made up of h20.
helium atoms, are they elementary particles?
NO
We know that are made up of protons and electrons
What about a hydrogen ion?
NO 1 proton (uud) and 1 neutrons (udd) which are made up of quarks
HADRONS
Each quark is an elementary particle and form composite particles known as HADRONS. A HADRONS is a term for any nuclear particle (e.g. Neutrons and Protons).
When a composite particle of 3 quarks is formed it is called a what
BARYON
Definition of composite particle
refer to particles that have composition – that is particles which are made of other particles. For example, a carbon-14 atom is made of six protons, eight neutrons, and six electrons.
Anti-particles
a particle with the same mass and opposite charge and/or spin to a corresponding particle, for example positron and electrons
what is a composite particle consisting of one quark and one antiquark
MESON
elementary particles governed by the weak nuclear force and if charged also electromagnetism.
Leptons
Electron, tau, muon have what charge
negative charge
Positrons, antitau, antimuon have what charge
a positive charge.
why is a proton not an elementary particle but an electron is?
The proton, for example, is not an elementary particle, because it is made up of three quarks, whereas the electron is an elementary particle, because it seems to have no internal structure.
what are the four forces
- Electromagnetism
- Strong nuclear force
- Weak nuclear force
- Gravity
what force are quarks governed by
strong nuclear force
what force are leptons govern by
respond only to the electromagnetic force, weak force, and gravitational force
how do you find a lepton number
by adding all of the leptons and subtracting all anti-leptons
particle with what are influenced by electromagnetism
charge
electrons repel electrons - this is a particle interaction between 2 what
leptons
Pair production
gamma radiation spontaneously produces matter and antimatter particles
annihilation
reaction in which a particle and its antiparticle collide and disappear, releasing energy.
postulates of special relativity
the laws of physics are same in all inertial frames of reference. the speed of light is constant for all observers in an inertial frame of reference
describe general relativity in terms of what it says about space-time and objects of large mass
space and time are considered to be a 4 dimensional fabric that is warped by objects of large mass
describe General Relativity in terms of what it says about being in a planets gravitational field and accelerating frames of reference
experience is identical
- with special relativity, where does time get stretched out? For the observer who is moving at close to light speed or the observer who is watching an object move at close to light speed?
the observer who is watching an object move at close to light speed
Arrange in order of increasing distance: megaparsec, light year, astronomical unit, parsec
astronomical unit, light year, parsec, mega parsec
The Cosmic Background Radiation is evidence of what
the big bang
Light travels at what
3 x 108 ms-1
Speed =
distance / time
definition of astronomical unit
For general reference, we can say that one astronomical unit (AU) represents the mean distance between the Earth and our sun.
Light year
are a measurement of the distance light can travel in a year.
parsec
1 parsec is the distance to a star that would give a parallax angle from opposite sides to our orbit around the sun
1 parsec = how many light years
3.26 light years
A megaparsec is what
A megaparsec is one million parsecs, or about 3,260,000 light years.
the balloon experiment shows us what about the universe
how it is always expanding
the static on a TV shows what
Cosmic Background Radiation
The Plank Epoch encompasses the time period from
0 to 10-43 seconds.
The separation of the strong nuclear force led to what
particle reactions that formed W, Z and Higgs boson particles.
the separation of the weak nuclear force led to what
the electromagnetic force finally occurs
Quark Epoch is where we begin to see the rapid formation of quarks and anti-quarks do what
these particles collide and annihilate one another on impact
How did elements like carbon and oxygen form in the early stelliferous period?
the nuclear fusion of hydrogen and helium into bigger elements
what two atoms came into existence first
Hydrogen and helium
Describe how the first stars actually formed
gravity slowly shepherded the densest regions of hydrogen gas into compact clouds, which ultimately collapsed to form the first stars.
What process (2 words) begins when a huge dense mass of hydrogen and helium gas is under so much gravitational pressure and extreme temperatures due to that pressure.
nuclear fusion
- How were the first stars different to current stars?
a. Composition?
they from hydrogen and helium
- How were the first stars different to current stars?
b. Size?
they were larger and hotter up to 30-100 times the mass of the sun
- How were the first stars different to current stars?
Life Span?
life span was very short
- How were the first stars different to current stars?
Temperature?
50 times hotter than the sun
- How were the first stars different to current stars?
Type of light they gave off?
ultra violet
- What change did the first stars do to most of the matter known as the intergalactic medium?(Reionisation)
turns atoms into irons
How did elements like carbon and oxygen form in the early stelliferous period
nuclear fusion of hydrogen and helium into bigger elements
definition of nuclear fusion
the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy.
era of nucleosynthesis
were the first nucleus were formed
Brown dwarf
astronomical object that is intermediate between a planet and a star. aka failed star
mass of brown dawrf
Brown dwarfs usually have a mass less than 0.075
Brown dwarfs
are failed stars about the size of Jupiter, with a much larger mass but not quite large enough to become stars.
Red dwarf
a star having substantially lower surface temperature, intrinsic luminosity, mass, and size than the sun.
Black Dwarfs
• Black Dwarfs are, in theory, a white dwarf that has cooled to the extent that it emits no light or heat.
Supernova
supernova is the explosion of a star. It is the largest explosion that takes place in space.
Neutron stars
Neutron stars are formed when a massive star runs out of fuel and collapses. The very central region of the star – the core – collapses, crushing together every proton and electron into a neutron.
black holes
When a star runs out of nuclear fuel, it will collapse. If the core, or central region, of the star has a mass that is greater than three Suns, (after the Supernova) no known nuclear forces can prevent the core from forming a deep gravitational warp in space called a black hole.
Population III stars
First stars
