Particle Physics Flashcards
How did the alpha particle scattering experiment show that atoms are mostly empty space?
Most of the alpha particles passed through the gold foil with little to deflection.
How did the alpha particle scattering experiment show that atoms have a small positively charged nucleus?
A very small number of the alpha particles were deflected by large angles to behind the gold foil.
How many times smaller than an atom is a nucleus?
About 100000.
How can you find the number of neutrons in an atomic nucleus?
The nucleon number - The atomic number.
What is the radius of a proton (r0)?
About 1.2fm.
In what range is the strong nuclear force attractive?
About 0.5fm to 3fm
What are the properties of antimatter?
It has the same mass as its matter counterpart but opposite charge.
What is a hadron?
A subatomic particle that experiences the strong nuclear force and is made up of quarks (eg protons or neutrons).
What is a lepton?
A fundamental subatomic particle that experiences the weak nuclear force (eg electrons or neutrinos).
What is the charge on an up quark?
+2/3
What is the charge on a down quark?
-1/3
What is a baryon?
A subatomic particle made up of 3 quarks.
What is a meson?
A subatomic particle made up of one quark and one anti-quark.
What happens in beta- decay in terms of quarks?
A down quark decays into an up quark, releasing an electron and an electron antineutrino.
What happens in beta+ decay in terms of quarks?
An up quark decays into a down quark, releasing a positron and an electron neutrino.
