<prompt> Half life of tritium is -10.2 years12.3 years15.5 years20.7 years  <response>: Ans is b i.e. 12.3 years Tritium hydrogen-3 is a radioactive isotope of hydrogen. The nucleus of tritium sometimes called a triton contains one proton and two neutrons. Whereas the nucleus of protium contains one proton and no neutrons. Tritium has a half-life of 12.3 years. Tritium is used as a radioactive tracer, in radioluminescent light sources for watches and instruments, and, along with deuterium, as a fuel for nuclear fusion reactions with applications in energy generation and weapons.Half life of some important radioisotopes Phosphorus P-32 - 14.3 days Strontium Sr - 28 days Yttrium Y-90 - 2.54 days Radium Ra-226 - 1622 years Iodine 1-131 - 8 days Iridium Ir-192 - 74.5 days Cobalt Co-60 - 5.2 years Cesium Cs-137 - 30 years Technitium Tc-99 - 6 hours 