Particle Physics Flashcards
How is Rutherford’s Scattering experiment conducted?
beam of alpha particles from a radioactive source were targeted towards a thin gold foil
Rutherford’s: Most alpha particles went straight through the gold foil, what does this show?
gold atoms were mostly emptty space
Rutherford’s: Some alpha particles were scattered at angles greater than 90 degrees, what does this show?
each gold atom has a positive nucleus with a radius less than about 10^-14m
Rutherford’s: What is the scattering of alpha due to?
electrostatic repulsion by the gold nucleus
What is the nucleus made up from?
neutrons and protons
What is a nucleon?
neutron or proton
What is the nucleus surrounded by?
cloud of electrons
What is equal in a neutral atom?
number of protons and electrons
How do you calculate the number of neutrons in an atom?
nucleon number - proton/atomic number
What is an isotope?
nuclei of the same element that have the same number of protons but different number of neutrons
What is the mass of a particle quoted in?
atomic mass units (u)
How much smaller is the volume of the nucleus than the volume of the atom?
10^15
Why is the mass of the atom approximately the same as the mass of the nucleus?
minuscule mass of electrons
What forces do protons within a nucleus experience?
large electrostatic repulsive forces
What force do all nucleons inside the nucleus experience?
strong nuclear force
When is nuclear force attractive?
up to 3fm
When is nuclear force repulsive?
below 0.5fm
What is the antiparticle of an electron?
positron
What is the antiparticle of a proton?
antiproton
What is the antiparticle of a neutron?
antineutron