Particle physics and quantum physics Flashcards
(25 cards)
What is an antiparticle?
A particle of same mass, opposite charge, opposite lepton/baryon number
What is the anti particle of an electron? (e-)
Positron (e+)
What is different to charges inside the nucleus of atom to others in the real world?
Instead of repelling eachother they stay together
What is the strong nuclear force?
The force that keeps atoms together inside the nucleus of an atom but prevents them crushing eachother
What distance is the strong nuclear force repulsive?
0-0.5 fm (f=x10^15)
What distance is the strong nuclear force attractive?
0.5-3 fm (f=x10^15)
What types of particles experience the strong force?
Hadrons
What types of particles don’t experience the strong force?
Leptons
What are the hadrons and what is their composition?
Baryons: Baryon number of 1
Experience the strong force
3 Quarks
Protons and Neutrons
Mesons: Quark-antiquark pair
Pions and Kaons (2 quarks)
Kaons always have a strange particle
What particle always has a strange particle?
Kaons
How much bigger is a muon than an electron?
200 times
What is the quark composition of a proton?
UUD
What is the quark composition of a neutron?
UDD
Which of the baryons is the only stable one?
Proton
What is an isotope?
An atom with the same number of protons but different neutron number
If the radius of a nucleus is doubled then the number of nucleons increases by ?
8
What is the radius of a nucleus?
1x10e-15
What order of magnitude is the radius of an atom?
1x10e-10
State what kind of experiment would confirm that electrons have a wave-like nature.
Diffraction
State why it is easier to demonstrate the wave properties of electrons than to demonstrate the wave properties of protons.
-Easier to obtain electrons (to accelerate)
-OR easier to get λ same size as scattering object
What is meant by an excited atom?
An electron in an atom/atom is at a higher level than the ground state
Describe the process by which mercury atoms become excited in a
fluorescent tube.
Electrons (or electric current) flow through the tube
and collide with orbiting/atomic electrons or mercury atoms
raising the electrons to a higher level (in the mercury atoms)
What is the purpose of the coating on the inside surface of the glass in a fluorescent tube?
Photons emitted from mercury atoms are in the ultraviolet (spectrum) or are high-energy photons
These photons are absorbed by the powder coating
or the powder coating changes frequency/wavelength
and the powder coating emits photons in the visible spectrum
How are hadrons and leptons different
