Answer :
Final answer:
Cesium-137 decays into barium-137 (Ba-137) through beta decay, and the nuclear equation for this process includes the emission of a beta particle and a gamma ray. so the correct option is a) Ba-137.
Explanation:
If cesium-137 undergoes beta decay, it will decay into barium-137 (Ba-137). The nuclear equation that represents this decay is ^{137}_{55}Cs \rightarrow ^{137}_{56}Ba + ^0_{-1}\beta + \gamma In this equation, ^{137}_{55}Cs represents cesium-137, ^{137}_{56}Ba represents the daughter isotope, barium-137, ^0_{-1}\beta represents the beta particle (electron) emitted during decay, and \gamma represents the emission of a gamma ray. The atomic number of cesium increases by one upon emitting a beta particle, becoming barium, which has one more proton than cesium.
