Nuclear Physics 3 Flashcards
Graph of intensity against angle for electron diffraction by a nucleus
Same graph as graph for diffraction pattern of electron diffraction
But one is simply zoomed in around the angle of first maximum
What is the mass defect
The difference between the mass of a nucleus and the sum of the masses of its constituents
The mass of the nucleus is always less
What is binding energy
The energy required to separate the nucleus into its constituents
The energy released when a nucleus is formed from its constituents
Which is the energy equivalent to the mass defect
Why does a mass defect exist
As nucleons in a nucleus need less energy due to the existence of the strong nuclear force keeping them together
What is 1 u
What is it defined as
1 atomic mass unit
1/12 the mass of a carbon - 12 atom
What is 1 u in kg and MeV
1u =
- 661x10-27 kg
- 5 MeV
What is nuclear fission
The splitting of a large unstable nucleus into 2 daughter nuclei
Why is energy released during nuclear fission
As the smaller daughter nuclei have a higher binding energy per nucleon
So nucleons in the larger nucleus have less energy
What is nuclear fusion
Where 2 smaller nuclei join together to form 1 larger nucleus
What is a condition necessary for nuclear fusion and why
Must occur at a very high temperature
A massive amount of energy is required to overcome the electrostatic force of repulsion between nuclei.
Why is energy released in nuclear fusion
As the larger nucleus has a much higher binding energy per nucleus
So nucleons in the larger nucleus have less energy (P.E) so energy must be released
Graph for binding energy per nucleon
What does the graph show about fission and fusion
The smaller nuclei produced in fission (Moving from the right of the graph towards Fe as mass gets less) have a higher binding energy
The larger nuclei produced in fusion (Moving from the left of the graph towards Fe as mass gets much more) have less binding energy
What is binding energy per nucleon
The binding energy of a nucleus divided by the number of nucleons in the nucleus
What element has the highest binding energy per nucleon
What does this mean
Fe 56
Nuclei smaller than iron can undergo fusion, while elements larger than iron can undergo fission
How is nuclear fission used in electricity production
What are the problems with it
Used in nuclear power plants to produce electricity without emitting greenhouse gases
Daughter nuclei produced are radioactive and need to be safely stored for 1000’s of years
Possibility of a meltdown
