Physics

3. _____ charges attract.
4. Ionizing radiation is _____ for health. (dangerous/safe)
6. The heavy core of an atom consisting of protons and neutrons.
7. The type of radiation that does not involve particles and only transfers energy with very high penetration.
11. Atoms with the same number of protons but a different number of neutrons (could be heavier or lighter).
12. Alpha particles can be stopped through a thin sheet of ____.
14. This is equal to the number of protons.
16. Charge of an electron.

1. A nuclear reaction in which two nuclei combine to form a heavier nucleus, releasing energy in the process.
2. High energy electron ejected from the nucleus, slightly ionizing and penetrating.
5. A nuclear reaction in which a heavy nucleus splits spontaneously or because of colliding with another particle, releasing energy in the process.
8. The most ionizing type of radiation with weak penetration power.
9. Charge of a proton.
10. Which element has a nucleus identical to an alpha particle?
13. The most prominent source of background radiation.
15. After 16 years, an atom with initially 100g of radioactive material has become 25g. What is its half-life? (____ years)