Particle Physics

Question 1

Explain why energy levels are negative.

Answer 1

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.

Question 2

Describe the nature of the strong nuclear force

Answer 2

It acts between quarks/nucleons/hadrons ‘Short-range’ force. Repulsive below (about) 0.5 fm. Attractive up to (about) 3 fm

Question 3

Name a hadron found in the nucleus of an atom and state its quark combination.

Answer 3

proton = u u d or neutron = u d d

Question 4

What are the 4 fundamental forces?

Answer 4

Strong nuclear, weak nuclear, electromagnetic, gravitational.

Question 5

What is a hadron?

Answer 5

Any particles made up of quarks.