Physical Science:

In nuclear reaction emits alpha, beta, and other high enegy waves or particles that can knock out atoms or molecules to form ions. These ions come under ionizing radiation. Such radiation can damage living cells and affects protien or DNA molecules. There are several types of radiation, including: alpha radiation, beta radiation, gamma radiation, X-rays, nuclear radiation, and cosmic radiation, etc. Cosmic radiation is high-energy radiation that originates from outside of the Earth’s atmosphere. It consists of high-energy particles, including protons and electrons, that are produced by the Sun and other astronomical sources. Radiation doses doses are measured in the Sievert (Sv) unit. The sievert is used to describe the amount of ionizing radiation that has been absorbed by a material. The another unit of doses is Rads (short for "radiation absorbed dose"). It is used to quantify the amount of energy deposited in a material by ionizing radiation per unit mass. One rad is 0.01 joule of energy deposited in one kilogram of tissue. That is \(1 \,rad = 0.01 \,J/kg\) of energy deposited on the tissue. One sievert is equal to 100 rads. The sievert is the standard unit of measurement used to describe the amount of ionizing radiation that has been absorbed by the human body, and it is used to evaluate the potential health risks associated with exposure to ionizing radiation. We receive 3.1 mSv per year from natural radiation resources, 3.1 mSv per year from medical and dental x-rays, and 0.4 mSv from mammogram. The total unavoidable radiation doses are about 6.2 mSv per year. The allowed safe radiation dose limit for a healthy human is \(20 \,mSv\text{.}\) The risk of radiation induced cancer is much smaller than other hazardous activities such as smoking. Sources of radiation exposure is given in Figure 7.2.6