Choose the correct option for the following Assertion (A) and Reason (R).

Question

G1 Physics · Accepted Answer

Natural uranium is predominantly U-238 and contains only a much smaller fraction of U-235. U-235 is fissile with thermal neutrons and can readily sustain fission under suitable reactor conditions. U-238 is mainly fertile for thermal neutrons; after neutron capture it can ultimately form Pu-239 rather than simply behaving like U-235. Therefore not every uranium nucleus in natural uranium can be treated as an equally effective thermal-neutron fission fuel. Both Assertion and Reason are true, and…