Nuclear Physics Flashcards
What conclusions were drawn from Rutherford’s alpha particle scattering?
Atoms are mostly empty space. (Most particles passed straight though)
The centre/nucleus of an atom is positively charged. (Some particles deflected by a large angle)
The nucleus is massive. (Some particles deflected > 90°)
What is the range of alpha radiation?
2cm-10cm
What is the range of beta radiation?
~ 1m
What is the range of gamma radiation?
Infinite. Follows inverse square law.
What are advantages of using radiation?
Production of materials - Different penetrating powers can be used to monitor the thickness of materials.
Sterilisation of surgical equipment - gamma radiation kills bacteria.
Radiation therapy - gamma radiation can be used to kill cancerous cells.
How must radioactive source be handled safely?
Long handled tongs.
Source stored in lead-lined container when not in use.
Keep source far away from everyone.
Never point the source at others.
What must be taken into consideration when taking the count of a radioactive source?
Background count due to background radiation.
Corrected count = Total Count - Background Count
What are some source of background radiation?
Radon gas.
Artificial sources (nuclear weapons).
Cosmic rays.
Rocks.
What is the decay constant of a radioactive nucleus?
The probability of a nucleus decaying per unit of time.
What is the activity of a sample?
The number of nuclei that decay per second.
What is the closest approach of a charged particle (nuclear radii)?
The point at which a particle stops (no KE) is it’s distance of closest approach.
What is the equation for radius of an atom using electron diffraction?
Sinx = 0.61λ/R
