Mass defect and nuclear binding energy
9 flashcards to master this topic
State Einstein's mass-energy equivalence equation and define each term.
E = mc², where E is energy (J), m is mass (kg), and c is the speed of light in a vacuum (approximately 3.00 x 10⁸ m/s). This equation shows that mass can be converted into energy and vice-versa.
Define 'mass defect' in the context of nuclear physics.
Mass defect (Δm) is the difference between the mass of the individual nucleons (protons and neutrons) in a nucleus and the actual mass of the nucleus. This 'missing' mass is converted into binding energy.
Define 'nuclear binding energy'.
Nuclear binding energy is the energy required to separate a nucleus into its constituent protons and neutrons. It is equivalent to the mass defect via E=mc².
Describe the general trend of binding energy per nucleon with increasing nucleon number (A).
Binding energy per nucleon increases sharply for light nuclei, reaches a maximum around A=56 (Iron, Fe), and then slowly decreases for heavier nuclei. This trend dictates the energy release during fusion and fission.
Explain the process of nuclear fusion.
Nuclear fusion is the process where two light nuclei combine to form a heavier nucleus. This process releases energy when the resulting nucleus has a higher binding energy per nucleon than the original nuclei (
Explain the process of nuclear fission.
Nuclear fission is the process where a heavy nucleus splits into two or more lighter nuclei. This process releases energy when the resulting nuclei have a higher binding energy per nucleon than the original nucleus (
Explain the relevance of binding energy per nucleon to nuclear reactions.
Nuclear reactions release energy if the binding energy per nucleon of the products is greater than that of the reactants. This is why fusion releases energy for light nuclei, and fission releases energy for heavy nuclei.
A nucleus has a mass defect of 0.005 u. Calculate the binding energy in MeV (Mega electron volts). (1 u = 931.5 MeV/c²)
Binding energy = Δm * c² = 0.005 u * (931.5 MeV/c²) / u * c² = 4.6575 MeV. Therefore, the binding energy is 4.6575 MeV.
Write a balanced nuclear equation representing the alpha decay of Uranium-238 (²³⁸U).
²³⁸₉₂U → ²³⁴₉₀Th + ⁴₂He. This equation shows Uranium-238 decaying into Thorium-234 and an alpha particle (Helium-4 nucleus).
Ready to test yourself?
Practice with MCQ questions to check your understanding of Mass defect and nuclear binding energy.
Take QuizStudy Mode
Rate each card Hard, Okay, or Easy after flipping.