Nuclear & Radioactivity
Physics · नाभिकीय और रेडियोधर्मिता · 16 facts
Radioactivity: spontaneous emission from unstable nucleus; Becquerel(1896)
Alpha(He nucleus), Beta(electron), Gamma(EM radiation)
Penetrating: alpha<beta<gamma; Ionizing: alpha>beta>gamma
Alpha:paper stops; Beta:aluminium; Gamma:thick lead/concrete
Marie Curie: Radium & Polonium; first woman Nobel; 2 Nobels
Half-life: time for half atoms to decay; constant per isotope
Fission: heavy nucleus splits; atom bomb, reactor
Fusion: light nuclei combine; Sun energy (4H->He)
E=mc2: mass to energy; basis of nuclear power
Chain reaction: controlled in reactor, uncontrolled in bomb
U-235, Pu-239: fissile materials
Carbon dating: C-14 half-life 5730 years for fossils
Reactor: fuel rod, moderator, control rod, coolant
India: Pokhran-I(1974), Pokhran-II(1998)
Nuclear plants: Tarapur, Kudankulam, Kalpakkam, Narora
Radioactive waste hazardous; needs safe storage thousands of years