Atomic And Nuclear Physics Flashcards
What is alpha radiation?
Same as a helium nucleus, with 2 protons and 2 neutrons.
Cannot pass through materials easily.
What does an alpha decay equation look like?
Atom loses 2 protons and 2 neutrons
E.g.
A A-4 4
. X —> Y + He
Z Z-2 2
What is bata radiation?
A fast moving election
Can pass through thin materials, but stopped by metals
What does a Beta decay equation look like?
Atomic number increases by one but mass number stays the same. + electron created.
What is gamma radiation?
Electro magnetic photon
Can pass through most materials, though lead stops it a bit.
What does a gamma decay equation look like?
No effect on atomic number or mass of the nucleus
What is background radiation?
The natural count of radiation.
List some sources of background radiation.
The sun
Soil
Bananas
Nuclear explosions
What is Half-life?
The time it takes for half the number of un-decayed radioactive atoms to decay.
How is radiation dangerous?
It’s ionising, damaging DND and causing mutations and cancer.
What is the most dangerous radiation type?
Alpha - most dangerous, heaviest and most ionising
What are some uses of radioactive isotopes?
Medicine, e.g radiotherapy
Sterilisation
Smoke detectors
What is nuclear fission?
When the nucleus of an atom is hit by a neutron, it splits in two and releases 2 or 3 more neutrons. These neutrons hit more nuclei and causes a chain reaction which releases a lot of energy.
How is half life calculated?
N= No
—-
2n
N= No. after ‘n’ half lives
No = No. in the beginning
n = number of half lives
What is nuclear fusion?
The joining of 2 small nuclei into a single nucleus, achieved by the high impact speeds of the small nuclei & release energy.
Label the apparatus of a scattering experiment.
(Check notes)
Should contain:
Travelling microscope
am counter
Gold foil
Alpha source
How is a scattering experiment carried out?
Alpha particles were emitted from a radioactive isotope and sent through a sheet of gold foil. Those that passed through were picked up by the am counter, while other bounced off.
What was learned from the scattering experiment?
Atoms were mostly empty space (most particles went through)
They had a small, positively charged nucleus (some electrons were repelled)
How do you calculate the activity of a substance after several half lives?
e.g. half life 8 hours activity 2043
t1/2 | time(hr)|Activity
0 | 0 | 2043
1 | 8 | 1024
2 | 16 | 512
3 | 24 | 256
