It is ionizing radiation on human body is that the energy absorbed is low but the biological effects are serious.
Ionizing radiation is made up of energetic subatomic particles, ions or atoms moving at relativistic speeds, and electromagnetic waves on the high-energy end of the electromagnetic spectrum. Ionizing radiation is categorized by the nature of the particles or electromagnetic waves that create the ionizing effect. These have different ionization mechanisms, and may be grouped as directly or indirectly ionizing. Properties of alpha, beta and gamma radiation. Alpha Particles. Alpha particles are strongly ionising but can be stopped by paper or skin. They have a strong positive charge (+2) and a mass of 4 (i.e. 4 times the mass of a proton). An alpha particle is in fact the same as a helium nucleus - 2 protons and 2 neutrons. Beta particles. Beta particles are electrons-but they are called beta particles to identify that they came from the nucleus of the atom. Ionizing (or ionising in British English) radiation is radiation that carries enough energy to free electrons from atoms or molecules, thereby ionizing them. Ionizing radiation is categorized by the nature of the particles or electromagnetic waves that create the ionizing effect. These have different ionization mechanisms, and may be grouped as directly or indirectly ionizing. Ionizing radiation is any type of particle or electromagnetic wave that carries enough energy to ionize or remove electrons from an atom. There are two types of electromagnetic waves that can ionize atoms: X-rays and gamma-rays, and sometimes they have the same energy. Gamma radiation is produced by interactions within the nucleus, while X-rays are produced outside of the nucleus by electrons. There are officially two types of ionizing radiation that are energetic particles emitted during an interaction within the nucleus. The alpha particle is composed of two protons and two neutrons, or a helium nucleus.  Radioactive substances give out radiation all of the time. There are three types of nuclear radiation: alpha, beta and gamma. Alpha is the least penetrating, while gamma is the most penetrating. Nonetheless, all three are ionising radiation: they can knock electrons out of atoms and form charged particles. Radiation can be harmful, but it can also be useful-the uses of radiation include to: 1  detect smoke. Non-ionizing (or non-ionising) radiation refers to any type of electromagnetic radiation that does not carry enough energy per quantum (photon energy) to ionize atoms or molecules—that is, to completely remove an electron from an atom or molecule. Another suggested threshold is 33 electronvolts, which is the energy needed to ionize water molecules. The light from the Sun that reaches the earth is largely composed of non-ionizing radiation, since the ionizing far-ultraviolet rays have been filtered out by the gases in the atmosphere, particularly oxygen. Gamma rays, X-rays, and the higher ultraviolet part of the electromagnetic spectrum are ionizing, whereas the lower ultraviolet part of the electromagnetic spectrum, visible light (including nearly all types of laser light), infrared, microwaves, and radio waves are considered non-ionizing radiation. Ionizing radiation is categorized by the nature of the particles or electromagnetic waves that create the ionizing effect. These have different ionization mechanisms, and may be grouped as directly or indirectly ionizing. Alpha, beta and gamma. Radioactive atoms give out ionising radiations. However, it turns out that there are three distinct types of radiation, each with very different properties. We call these radiations alpha (a), beta (b) and gamma (g).  Characteristics. One characteristic of ionizing radiation on human body is that the energy absorbed is low but the biological effects are serious. For example after receiving a lethal dose of 10 Gy, the body temperature will only increase by 0.02 C but the dose may lead to death of all the exposed entities. The second characteristic is the latent biological effects of radiation. Acute biological effects can occur within several hours to several days while the long term effects usually appear several years after the exposure.
https://en.wikipedia.org/wiki/Ionizing_radiation http://www.s-cool.co.uk/a-level/physics/radioactivity/revise-it/what-is-ionising-radiation https://en.wikipedia.org/wiki/Ionizing_radiation http://www.physicscentral.com/explore/action/radiationandhumans.cfm http://www.bbc.co.uk/schools/gcsebitesize/science/edexcel/electromagnetic_spectrum/electromagneticspectrumrev5.shtml https://en.wikipedia.org/wiki/Non-ionizing_radiation https://en.wikipedia.org/wiki/Ionizing_radiation http://resources.schoolscience.co.uk/corus/14-16/rad/psch5pg2.html http://www.hko.gov.hk/education/dbcp/rad_health/eng/r4.htm
what is the characteristic of ionising radiations