Terrestrial radiation is maximum in-

Ans. is 'd' i.e., Kerala Terrestrial radiation Radioactive elements such as thorium, Uranium, radium and an isotop of potassium (K40) arc present in man's invironment, e.g., soil, rocks, boiling. o It is estimated that man derives about 50 mrad per year from terrestrial radiation. Area exists (Kerala in India) where the rock formation containing uranium, it can be as high as 2000, mrad a year.