Which of the following is a naturally occuring radioactive substance in the body in small quantities?: (A) Radium 226, (B) Bismuth 60, (C) Iodine 131, (D) Potassium 40
Answer is D. Sources of radiation exposure are: Natural sources and Manmade sources. The natural sources include cosmic rays, environmental (terrestrial and atmospheric) radiation, internal radiation (Potassium - 40 & Carbon -14) Man-made Radiation: Medical and dental: X rays, radioisotopes Occupational exposure Nuclear Misc: TV, Radio-active dial watches, Luminous markers Park's Textbook of Preventive and Social Medicine, 25th Edition, Pg 803