Tritium, of hydrogen-3, is prepared by bombarding lithium-6 with neutrons. a 0.250-mg sample of tritium decays at the rate of

Tritium, of hydrogen-3, is prepared by bombarding lithium-6 with neutrons. a 0.250-mg sample of tritium decays at the rate of 8.94 * 10 ^ 10 disintegrations per second. what is the decay constant (in per sec) of tritium, whose atomic mass is 3.02 amu?