PHY100H5 Lecture Notes - Lecture 15: Nuclear Reaction, Half-Life, Lise Meitner
Document Summary
Strong force: attraction between nucleons (protons & neutrons), short-range. Responsible for holding the nucleons (protons and neutrons) in the nucleus. Weak force: responsible for the disintegration of nuclei (radioactivity) Isotopes: variants of an element having the same z (# of protons), the number of neutrons differs. Half-life: the time in which 50% of the isotopes decay (ex. 6,000 years for 14c) n half-lives = (cid:883)(cid:884) years. Radiation damage: cancer, mutations, radiation sickness; dosage is measured in sievert (cid:894) (cid:448)(cid:895) (cid:374)or(cid:373)al dose 3 msv/year, lethal dose 1-10 sv (suddenly). Fusion = putting things together; fusion = breaking things apart. Nuclear fission: from an idea to a bomb. Gravitational potential energy is higher when something is farther, and is lower when something is closer (you need more energy to keep the farther body closer to you than the one that is closer) The separated neutron and proton have more energy compared to the nucleus; this is a form of nuclear energy.