hoe can we have counts lower than the background radiation?
337069
1. Background radiation is an average value.\nYou may be taking a count in place where the background is lower (e.g., in the partially shielded room).\n\n2. Background radiation AND counters are directional.\nFor example, let's say you live in the granite building and take a count in the direction of window. Your background comes mostly from granite, so counts become lower.\n\n3. Is your sample on a shielding material? Thick piece of metal or plastic, maybe?\nIf your sample is non-active, you are actually shielding background off and then measure what's left with a directional counter.
628925
That is the law of hughe numbers.\nAbout the decay of individual nucleus you can predicht nothing.\nHowever about a measurable amount of isotope you can give its half life time.
1053623
Phosphorous glows in the dark with a yellow-green light\n\nSome Radioactive things might glow in the dark but if you want a glow in dark substance safe around humans then yes, they cant be used
353533
If you could find a transition between an inverted state and a ground state of 1 joule, you could probably make a laser of that frequency. At this point, hard gamma rays are the limit we have done.
848476
Measuring the background radiation.\nCalculations involving half life.\nCalculating the energy of fusion and fission reactions.
599540
No, but there is a lot of radiation caused by computer monitors. Limit your use, but that may not be the reason why. Maybe you're allergic to some product that you used or ate.
250073
According to this site info...there is no need to worry.  You get way more radiation from everything else around you on a daily basis.\n\nhttp://www.pc.ibm.com/ww/healthycomputing/vdt14.html
270331
Three basic concepts apply to all types of ionizing radiation. When we develop regulations or standards that limit how much radiation a person can receive in a particular situation, we consider how these concepts might affect a person's exposure.  \n\nTime \nThe amount of radiation exposure increases and decreases with the time people spend near the source of radiation. \n\nIn general, we think of the exposure time as how long a person is near radioactive material. It's easy to understand how to minimize the time for external (direct) exposure. Gamma and x-rays are the primary concern for external exposure.\n\nHowever, if radioactive material gets inside your body, you can't move away from it. You have to wait until it decays or until your body can eliminate it. When this happens, the biological half-life of the radionuclide controls the time of exposure. Biological half-life is the amount of time it takes the body to eliminate one half of the radionuclide initially present. Alpha and beta particles are the main concern for internal exposure. \n\nDistance   \nThe farther away people are from a radiation source, the less their exposure. \nHow close to a source of radiation can you be without getting a high exposure? It depends on the energy of the radiation and the size (or activity) of the source. Distance is a prime concern when dealing with gamma rays, because they can travel long distances. Alpha and beta particles don't have enough energy to travel very far. \nAs a rule, if you double the distance, you reduce the exposure by a factor of four.  Halving the distance, increases the exposure by a factor of four.\n\nThe greater the shielding around a radiation source, the smaller the exposure. \n\nShielding simply means having something that will absorb radiation between you and the source of the radiation (but using another person to absorb the radiation doesn't count as shielding). The amount of shielding required to protect against different kinds of radiation depends on how much energy they have. \n\n \n(Alpha)\n\n A thin piece of light material, such as paper, or even the dead cells in the outer layer of human skin provides adequate shielding because alpha particles can't penetrate it. However, living tissue inside body, offers no protection against inhaled or ingested alpha emitters.\n    \n \n(Beta)\n\n Additional covering, for example heavy clothing, is necessary to protect against beta-emitters. Some beta particles can penetrate and burn the skin.\n   \n \n(Gamma) \n Thick, dense shielding, such as lead, is necessary to protect against gamma rays. The higher the energy of the gamma ray, the thicker the lead must be. X-rays pose a similar challenge, so x-ray technicians often give patients receiving medical or dental X-rays a lead apron to cover other parts of their body. \n\nSo in short the lead or other materials absorb the radiation vs. it being absorbed by your body.
689133
gamma radiation i think. alpha and beta are relatively weak.
927391
I'm very interested in becoming an radiology technologist, and from what I've heard, nowadays, the equipment is so good and improved that techs recieve little or no radiation.  There are actually little pins that techs can wear to track how much radiation they are exposed to, and like I said, with the new equipment, the pins have been very helpful in confirming the lack of exposure.
850091
I think that the answer must be YES.\n\nLet's assume that  these are dry cell batteries (so they are not losing any matter by evaoporation or gaining any by using oxygen in the atmosphere.\n\nSo no particles get in or out of the battery.  However, the battery, once spent, has lost some energy (perhaps by powering a torch which then gives out light and heat energy).\n\nAccording to Einstein's famous equation, E=mc^2.  So this amount of energy must be equivalent to (an extremely small) quantity of matter and the mass of the battery must have reduced by this amount.  It will not be measurable in ordinary circumstances and I am sure that other factors (eg dust particles settling on it, etc) would FAR outweigh this mass of the released energy.  But theoretically, yes, it would weigh less.\n\nOne gets a similar kind of balance in radioactive decay; a uranium nucleus decays into some other bits and pieces but the mass of the other bits and pieces is slightly less than the mass of the original uranium nucleus in order to account for the energy that is released (in the form of EM radiation).\n\nHope this makes sense.
526456
No, it's evidence of combustion.  Radioactive decay is usually invisible unless you have film there to see the particles given off.
580964
Gamma decay is probably the one you are after.\nTransitions in the energy levels of the nucleons is the process behind it.\nNuclear Magnetic Resonance is also a nuclear process and would make a better answer as the wavelength of radiation is much safer.
977864
The cloud chamber, also known as the Wilson chamber, is used for detecting particles of ionizing radiation. \n\nclick here:http://en.wikipedia.org/wiki/Cloud_chamber
927238
Alpha is least -- can be stopped by a piece of paper.  Beta is more so, and gamma more so yet -- it can take a foot or more of concrete to ablate gamma rays.
18888
You could make a cloud chamber. It's a chamber that's saturated with alcohol vapor so when a cosmic ray or radioactive particle enters the chamber it leaves a trail of mist like when a plane leaves a vapor trail. It does use dry ice and isopropyl alcohol though. It's kind of complicated but would be worth it in the end.
678624
The greatest threat of radioactivity to life as we know it is damage to the gene pool, the genetic make-up of all living species. Genetic damage from radiation exposure is cumulative over lifetimes and generations.\n\n     Some biomedical effects of radiation are well known. If the exposure is great enough, as it was for 200,000 people in Japan in 1945 and for the clean-up crew in Chernobyl, death can occur immediately or within days.\n\n     Even low-dose exposures are carcinogenic after extended exposure (Gofman 1990). The current generation, the one in utero, and all that follow may suffer cancers, immune system damage, leukemias, miscarriages, stillbirths, deformities, and fertility problems. While many of these health problems are on the rise, individuals cannot prove either increase in "background" radiation or specific exposure as the cause. Only epidemiological evidence is scientifically acceptable to impute cause. Perhaps the most extreme outcome over time would be simply the wholesale cessation of the ability to reproduce. Radiation is a known cause of sterility (Gofman 1981).\n\n     The quality of life of vast numbers of us may be affected by the increased burden of radioactivity we all bear. Many victims of radiation sickness do not show up in the statistics because the kind of symptoms experienced, while disabling, are not as significant as childhood leukemia, or stillbirths, or cancer, or birth defects. Nevertheless, lives of countless people have been affected by radiation exposure.\n\n     Beyond the physiological effects, the mental and emotional consequences of the trauma of exposure to invisible environmental contaminants in general, and radioactivity in particular, has been documented (Vyner 1988). One can only speculate about the spiritual consequences (Schell 1982; Lynch 1995).\n\n     "Background radiation" is a measurement of the accumulated radioactivity in the atmosphere from all sources combined: the sun, the earth, and all man-made explosions, leaks, accidents, purposeful ventings, and dumpings. The term, however, implies naturally occurring radiation is of no real concern. But before the Atomic Age there were no comprehensive measurements of naturally occurring radiation, so the use of this term obscures the reality that we already live in a contaminated world, and that radiation's effects are cumulative and irreversible.