1) Methods/equipment for radioactivity detection. For my high-school Chemistry studies, needs clarification. Geiger counter: A small chamber contains a high voltage electric field inside filled with inert gas. When ionizing particles/radiation enters the chamber, it will ionise the inert gas atoms, giving them a charge which will attract them to the cathode, conducting electricity which is registered on a meter. Cloud chamber: A chamber that contains super-saturated liquid vapours (water or alcohol?) and as radioactive particles/radiation enters the chamber they will ionize particles inside which can be traced. That's all I know, there's the Scintillation counter and radioactive film badges I'm not clear about and I heard there's something called the bubble chamber which apparently superseded the cloud chamber. 2) If lightning can create 100A in 0.1s, when a person is struck by this why have there been cases where this unfortunate victim has survived ? 3) Question: Define magnetic field strength (T) Answer: Magnetic flux density (Wb.m-2) True ?