E = Īm cĀ²E: J; Īm: kg ; c: m/s.
Use when: Īm is the difference between initial and final masses of the system considered.
Nuclear fission, fusion and energy
Distinguish the transformations of nuclei and link mass defect and energy.
What is happening?
Fission divides a heavy nucleus into lighter fragments, with possible emission of neutrons. Fusion brings together light nuclei. These transformations concern nuclei, and not simple exchanges of chemical electrons.
A nuclear balance must preserve the electric charge and the number of nucleons for the simple reactions studied. A decrease in rest mass of the system can correspond to released energy.
The formulas, with their conditions.
N(t) = Nā exp(āĪ»t) ; TĀ½ = ln(2)/Ī»N: number of cores; Ī»: sā»Ā¹; TĀ½: s.
Use when: Law of simple radioactive decay; does not by itself describe a controlled chain reaction.
Where is this principle used?
Fission power plant
Convert the energy released into usable heat.
Fusion and nuclear instrumentation research laboratory
Study nuclei and their interactions.
What to observe in the experiment
Compare a fission animation and a fusion animation: count the nuclei before and after, then check the balances.
References and readings
This sheet explains the principles and their assumptions. Educational simulation can simplify the process; an industrial model requires suitable data and validation.
Have you understood the essentials?
Only one correct answer per question. Answer all three questions, then view the answer key.
Intu Lab Ā· Understanding sheet Ā· Kimba Christian