Download 10th class physics chapter 18 exercise solved numericals notes pdf , national book foundation, federal board.
Unit 18: Radioactivity
Exercise Numericals Problems:
For solution please check pdf given at the end.
1. A radioactive substance has a half-life of eight months. In how much time, three-fourths of the substance will decay?
2. In 420 days, the activity of a sample of polonium (Po) to one eighth of its initial value. What is the half-life of polonium?
3. The half-life of radium is about 1600 years. In how much time, 25g will remain undecayed from the original 100g?
4. One eighth of the initial mass of a certain radioactive isotope remains undecayed after one hour. What is the half-life of isotope in minutes?
5. What proportion of a radium sample would be decayed after 8000 years? (Half-life of radium is 1600 years)
6. The half-life of a radioactive element is 15 days. If we have initially 50000 atoms of this radioactive atom then how many numbers of atoms are left over after 45 days?
7. What percentage of the original quantity of a radioactive material is left after five half lives approximately?