Question

One radioactive material that is produced in atomic bombs is the isotope strontium-90, which has a half-life of 28 years. If a person is exposed to strontium-90, it can collect in human bone tissue, where it can cause leukemia and other cancers. If an atomic bomb test site is contaminated by strontium-90, how long will it take for the radioactive material to decay to 30% of the original amount? (Round the growth factor to eight decimal numbers. Round your answer to the nearest year.)

Answer 1

a half life, ty = 28 years. het initial amount of the radio-active material be My gms. After t years the remaining material is Mgms where, M = Mett , where is the decay rate. Now, since the = 28 year & ŹMo = Mo étte → 2283 22 3 281 - In2 t 0.69314 7181 = 0.69364 = 0.0247552564 ~ 0.02475526 [ correct upto 80 places) After 30% decay of it's original the remaining amount is 20 x M. M. = 70 Mo ll
x
M. - Moeche , where 1 = 0.02475526 → it - 6 in () (40 t In (40) 0.02475526 = 14• 4080 4677 · yeass ~ 14.41 years . nearly 14.41 years will be needed for radio achive material decay to 30% of the original amount . . (Ans to ama