ATOMIC PHYSICS EXAM QUESTIONS WITH COMPLETE
SOLUTION
What happened when an election absorbs EM radiation?
Moves to a higher energy level
Firther away from the nucleus
What happens Shen an electron emits EM radiation?
Moves to a lower energy level
Closer to the nucleus
Nucleus size and mass (desc)
Tiny compared to the whole of the atom (about 1/10000 of the atoms size)
Hold nearly ALL of the atoms mass
Radius of an atom
1x10^-10m
Radius of a nucleus
1x10^-14
Positive ions
Ionisation- sometimes radiation can cause e- to be removed from an atom
When this happens, an atom loses e-'s to turn into a +ve ion
Isotopes
Different forms of the same element
Same no. Protons (same atomic no- bottom)
Diff no. Neutrons (diff mass no- top)
Affect of a neutron in an isoptope
Does NOT affect the charge since neutrons have no charge
Only affects mass
Radioactive decay
Random process where unstable atomic nuclei erase radiation to become
more stable
What is the activity of a radioactive substance
The rate at which it decays
Measured in Becquerels (Bq)
1Bq=1 decay per second
Count rate
the number of decays detected per second
Detected by a Geiger- Muller tube
What are alpha particles suitable for
SOLUTION
What happened when an election absorbs EM radiation?
Moves to a higher energy level
Firther away from the nucleus
What happens Shen an electron emits EM radiation?
Moves to a lower energy level
Closer to the nucleus
Nucleus size and mass (desc)
Tiny compared to the whole of the atom (about 1/10000 of the atoms size)
Hold nearly ALL of the atoms mass
Radius of an atom
1x10^-10m
Radius of a nucleus
1x10^-14
Positive ions
Ionisation- sometimes radiation can cause e- to be removed from an atom
When this happens, an atom loses e-'s to turn into a +ve ion
Isotopes
Different forms of the same element
Same no. Protons (same atomic no- bottom)
Diff no. Neutrons (diff mass no- top)
Affect of a neutron in an isoptope
Does NOT affect the charge since neutrons have no charge
Only affects mass
Radioactive decay
Random process where unstable atomic nuclei erase radiation to become
more stable
What is the activity of a radioactive substance
The rate at which it decays
Measured in Becquerels (Bq)
1Bq=1 decay per second
Count rate
the number of decays detected per second
Detected by a Geiger- Muller tube
What are alpha particles suitable for
