Particle Physics Flashcards
1
Q
Explain why energy levels are negative.
A
The electron is bound to nucleus. It represents the energy electron must gain to leave the atom. The total energy of electron in atom is less than that of a free electron.
2
Q
Describe the nature of the strong nuclear force
A
It acts between quarks/nucleons/hadrons ‘Short-range’ force. Repulsive below (about) 0.5 fm. Attractive up to (about) 3 fm
3
Q
Name a hadron found in the nucleus of an atom and state its quark combination.
A
proton = u u d or neutron = u d d
4
Q
What are the 4 fundamental forces?
A
Strong nuclear, weak nuclear, electromagnetic, gravitational.
5
Q
What is a hadron?
A
Any particles made up of quarks.
