Particles and Waves Part 1 (Forces on charged particles, standard model, nuclear reactions, spectra) Flashcards
What is the difference between fermions and bosons?
Fermions are matter particles - all matter in the universe is made from fermions.
Bosons are force-mediating particles - bosons are responsible for the four fundamental forces.
Describe the right-hand-rule (for a negative charge in a magnetic field).
Thumb - thrust
First finger - field
Second finger - electron flow
Is the line spectrum shown an example of emission or absorption?
This line spectrum is an emission spectrum (light is emitted by a particular element).
Describe how energy is produced during a nuclear fission reaction.
In nuclear fission, a large unstable nuclei splits apart to form two (or more) smaller nuclei and one or more neutrons.
The total mass of the products after the reaction is less than the total mass of the products before the reaction.
This difference in mass is converted into energy (E = mc2).
How many different types of quark are there?
Six.
Up, down
Charm, strange
Top, bottom
What is a hadron?
A hadron is a composite particle made of quarks.
What are the two groups of fundamental particles?
Quarks and leptons are the two groups of fundamental particles.
What is the unit for potential difference?
The unit for potential difference is volts (V).
Complete the following:
Moving charges experience a ………………… in a magnetic field.
Moving charges experience a force in a magnetic field.
When viewing the sun using a spectroscope, this pattern is observed.
What does this pattern show and what does it tell us about the sun?
This is an absorption spectrum.
Different lines show the frequencies that have been absorbed by gases in the sun’s upper atmosphere.
This allows elements in the sun’s atmosphere to be identified.
Which three quarks make up a proton?
A proton is made from two up quarks and one down quark.
In the energy level diagram shown, if an electron moved from E2 to E0 , would the electron gain or lose energy?
The electron would lose energy (a photon would be emitted).
The mass of a Higgs boson is 132 times bigger than the mass of a proton.
How many orders of magnitude bigger is the Higgs boson than the proton?
The Higgs boson is two orders of magnitude bigger than the proton.
(132 = 1.32 x 10<strong>2</strong>)
In Physics, what is a ‘field’?
A field is a region where an object experiences a force.
Which three quarks make up a neutron?
A neutron is made from one up quark and two down quarks.
What happens when a matter particle and an anti-matter particle come together?
Annihilation (resulting in the particles beign destroyed and converted into energy).
In a particle accelerator (such as the Large Hadron Collider), how are the particles accelerated?
In a particle accelerator, the particles are accelerated using an electric field.
What are the four fundamental forces in the Standard Model?
The four fundamental forces in the Standard Model are
- gravitational
- electromagnetic
- strong nuclear
- weak nuclear
A positron is the anti-particle of the electron.
In what way is the positron similar to, and different from, the electron?
The positron has the same mass but opposite charge from the electron.
What name is given to the reaction shown?
Nuclear fission (splitting apart of a larger nucleus into smaller ‘fragments’, releasing neutrons and energy).
What name is given to the type of spectrum shown here?
A continuous spectrum.
In a particle accelerator (such as the Large Hadron Collider), what is used to control the direction of the particles?
In a particle accelerator, a magnetic field is used to control the direction of the particles.
In diagrams showing magnetic fields, what do these symbols represent?
The ‘cross’ show magnetic field lines going into the page.
The ‘dot’ shows magnetic field lines coming out of the page.
By referring to the energy level diagram shown, explain how many lines would be observed in a line spectrum for this element.
There would be 6 lines.
There are six possible transitions for the energy level diagram shown.
- E3 to E2E2 to E1E1 to E0
- E3 to E1 E2 to E0
- E3 to E0
Describe the Bohr model of the atom.
Give as much detail as possible.
- The nucleus is positively charged
- Electrons are restricted to particular energy levels (orbits)
- The further from the nucleus the electron orbits the more energy the electron must have to stay in that orbit.
- electrons move between energy levels emitting (or absorbing) energy in the form of a photon
In an energy level diagram for an atom, what name is given to E0?
Ground state.
What name is given to the reaction shown?
Nuclear fusion (two smaller nuclei joining together, releasing energy).
Explain, in terms of electrons and energy levels, how a spectrum like the one shown here is produced.
When light is shone at a particular element, certain frequencies of light are absorbed.
Each black line indicates a particular transition where photons of one frequency have beenn absorbed and electrons have been raised to a higher energy level.
By making reference to the energy level diagram shown, explain how a line spectrum is produced when viewing light emitted by a particular element.
- Electrons can drop from a higher energy level to a lower one.
- Each particular ‘drop’ produces a photon of a certain energy and therefore of a specific frequency.
- Different transitions (drops between energy levels) produce photons of different energy and frequency.
- In a line spectrum, each line is the result of many photons making one particular transition. Different transitions produce different lines in the spectrum.
In the diagram, what do the lines represent?
The lines represent the direction of force a positively-charged particle would experience in that field.
What name is given to the type of spectrum shown here?
An absorption spectrum - because the black lines show the frequencies of light that have been absorbed.
(it is also an example of a line spectrum)
In the line spectrum shown, explain why some coloured lines are brighter than others.
Each line is caused by a transition of an electron from a higher energy level to a lower energy level.
If a line is brighter, it means that more electrons (per second) are making that particular transition than other ones.
