141830
Descripción
Fichas por eimearkelly3, actualizado hace más de 1 año
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Creado por eimearkelly3
hace más de 11 años
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| Pregunta | Respuesta |
| Henri Becquerel | Uranium salts emit radiation --> photographic plate |
| Radiation | The spontaneous breaking up of unstable nuclei resulting in the emission of radiation |
| What elements were isolated by Marie and Pierre Curie? | Polonium, Radium |
| What are the three types of radiation? | Alpha, beta, gamma |
| What is used to detect radioactivity? | A Geiger-Müller Tube |
| How does this tube work? | A gas is ionised by alpha, bet or gamma radiation and the resulting electric current is amplified and detected. |
| Alpha particles or... | helium nuclei (2 protons and 2 neutrons) |
| Properties of alpha particles | Positively charged Can't penetrate the skin / paper (pentrating ability = low) Damage human cells Are deflected in a magnetic or electrical field |
| Uses of alpha particles | In smoke detectors (Americium 241) |
| How does a smoke detector work? | Smoke detectors contain a radioactive source - Am-241, and a detector. They sense a change in the amount of radiation (alpha particles) reaching the detector in the presence of smoke. |
| What are the harmful effects of alpha particles? | Cause cancer, e.g. radon-alpha emitter causes lung cancer |
| Beta particles or... | electrons |
| Properties of beta particles | Moderate pentrating ability (stopped by 5mm aluminium) Negative charge Delflected in magnetic/electrical fields |
| Uses of beta particles | Carbon-14 dating All living organisms contain Carbon-14 and Carbon-12 When the organism dies, the carbon-14 will decay The ratio of Carbon-14 to Carbon-12 gives the age of the organism. |
| Harmful effects of beta particles | Cause cancer |
| Gamma rays are... | High energy electromagnetic radiation |
| Properties of gamma rays | No charge High penetrating ability (stopped by lead) No effect in magnetic/electrical fields |
| Uses of gamma rays | Food preservation by irridation (Cobalt-60) Cobalt-60 used in the treatment of cancer |
| The differences between chemical and nuclear reactions | In a chemical reaction, the reaction involves a change in the distribution of electrons --> no new element can be formed In a nuclear reaction, the reaction involves changes in the nucleus --> new elements can be formed |
| Radioisotopes | Unstable, radioactive isotopes |
| Half-life of a radioactive isotope | The amount of time it takes for half of the atoms in the sample to decay e.g. Am-241 has a half-life of 400 years |
| Background radiation | Radiation that surrounds us all the time Sources include: the decay of radioisotopes in rocks resulting in the emission of radon gas Nuclear waste Weapons testing Medical sources such as the use of cobalt-60 in cancer treatment and in medical X-rays. |
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