Date | May 2021 | Marks available | 1 | Reference code | 21M.2.SL.TZ1.5 |
Level | Standard level | Paper | Paper 2 | Time zone | 1 |
Command term | Outline | Question number | 5 | Adapted from | N/A |
Question
Radioactive uranium-238 produces a series of decays ending with a stable nuclide of lead. The nuclides in the series decay by either alpha (α) or beta-minus (β−) processes.
The graph shows the variation with the nucleon number A of the binding energy per nucleon.
Uranium-238 decays into a nuclide of thorium-234 (Th).
Write down the complete equation for this radioactive decay.
Thallium-206 decays into lead-206 .
Identify the quark changes for this decay.
Outline why high temperatures are required for fusion to occur
Outline, with reference to the graph, why energy is released both in fusion and in fission.
Uranium-235 () is used as a nuclear fuel. The fission of uranium-235 can produce krypton-89 and barium-144.
Determine, in MeV and using the graph, the energy released by this fission.
Markscheme
✓
Allow He for alpha.
udd→uud
OR
down quark changes to up quark ✓
links temperature to kinetic energy/speed of particles ✓
energy required to overcome «Coulomb» electrostatic repulsion ✓
«energy is released when» binding energy per nucleon increases
any use of (value from graph) x (number of nucleons) ✓
✓