Physics Unit 5 Radioactivity 2.5 / 5 based on 2 ratings ? PhysicsRadioactivityA2/A-levelAQA Created by: Nicola HansonCreated on: 14-04-13 17:26 How many protons and neutrons are in an alpha particle? 2 protons, 2 neutrons 1 of 17 Before Rutherford's experiment what was the popular structure for the atom? Plum pudding 2 of 17 Why is a vacuum needed for the alpha scattering experiment? Alpha particles scatter off of air particles 3 of 17 What is understood about the atom when most alpha particles pass through gold foil Most of the mass of an atom is concentrated in the nucleus 4 of 17 What is understood about the atom when some alpha particles deflect by more than 90 degrees The nucleus is positive 5 of 17 What is the range of an alpha particle? A few cm 6 of 17 What is the range of a beta particle? Up to a meter 7 of 17 What is the range of a gamma particle? Infinite 8 of 17 What are the effects of ionisation on the body? Destroys cell membrane and damages DNA 9 of 17 In radioactivity what does the symbol lambda stand for? Probability that a nucleus decays per second 10 of 17 What is the half life of a nucleus? Time for activity to decrease by a half 11 of 17 Why is alpha radiation not used for medical tracers? Can't penetrate the skin 12 of 17 Why do substances for medical tracers have a 6 hour half life? Stable enough to make measurements and decays away after use 13 of 17 How do nuclei become more stable? Emit alpha, beta and gamma radiation 14 of 17 Why do nuclei emit photons? They have too much energy, which photons take away 15 of 17 What is used to determine a nuclear radius Electron diffraction 16 of 17 What is the de Broglie wavelength of electrons in electron diffraction? 10^-15m 17 of 17
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