The half-life for gallium-67, a radioisotope, is 78.25 hours. How much of a 56.7 sample of gallium-67 would remain after 359 hours?

The half-life of radioactive strontium-90 is 28.8 years. How long would it take when only 16.5% of the original strontium-90 sample remains?

The half-life of nickel-63 is 100.1 years. If there are 100 grams of nickel-63 present at a certain time, how grams of nickel-63 will remain in 400.4 years? 50.0 12.5 6.25 25.0 It will all be gone

The currently accepted value for the half-life of radiocarbon is 5,730 years. Based on that information, which of the following conclusions is correct. 1. In 2,865 years, the entire original amount of carbon-14 in the sample will be gone. 2. In 11,460 years, the entire sample will be another element. 3. In 5,730 years, half of the original sample of carbon will be gone. 4. In 5,730 years, half of the original amount of carbon-14 in the sample will be gone.

Strontium-89 is a beta emitter with a half-life of 50.6 days that is used in bone cancer treatment. How many days will it take for a 69.6 mg sample of Sr-89 to decay to 0.148 mg?​ (Assume no excretion of the nuclide from the body).