half life multiple choice
1. Which sample will decay least over a period of 30 days?
a. 10g of I-131
b. 10g of P-32
c. 10g of Rn-222
d. 10g of Au-198
2. A sample of ^131 I decays to 1.0 gram in 40 days, What was the mass of the original sample?
a. 8.0g
b. 16g
c. 32g
d. 4.0g
3. What is the number of half-life periods required for a sample of a radioactive material to decay to one-sixteenth its original mass?
a. 8
b. 16
c. 3
d. 4
4. In how many days will a 12-gram sample of 131 / 53 I decay, leaving a total of 1.5 grams of the original isotope?
a. 24
b. 8.0
c. 16
d. 20
5. As a sample of the radioactive isotope ^131 I decays, its half-life
a. decreases
b. increases
c. remains the same