Problem 15
Although bismuth is generally considered stable, its only natural isotope, bismuth-209, is estimated to have a half-life of \(1.9 \times 10^{19} \mathrm{y}\). If the universe is estimated to have a lifetime of 1.38 \(\times 10^{10} \mathrm{y}\), what percentage of bismuth- 209 has decayed over the lifetime of the universe?
Problem 16
Name two isotopes that contribute to the radioactivity in our bodies.
Problem 16
The most common isotope of uranium (uranium-238) has a half-life of \(4.5 \times 10^{9} \mathrm{y}\). If the universe is estimated to have a lifetime of \(1.38 \times 10^{10} \mathrm{y}\), what percentage of uranium- 238 has decayed over the lifetime of the universe?
Problem 16
Which penetrates matter more deeply-alpha particles or gamma rays? Suggest ways to protect yourself against both emissions.
Problem 17
Define nuclear fission.
Problem 18
Explain how a Geiger counter works to detect radiation.
