Mantles for gas lanterns contain thorium, because it forms an oxide that can survive being heated to incandescence for long periods of time. Natural thorium is almost 100% 232Th , with a half-life of 1.405 × 1010 y. Randomized Variablesm = 270 mgIf an average lantern mantle contains 270 mg of thorium, what is its activity in Bq?

Hlf-life time of radioactive element is Mass of element is Note:Molar mass of is Avogadro's number is Find:Activity in units of The term "decay constant" refers to the ratio of the number of radioactive atoms that disintegrate in a short amount of time to the number of atoms of the same kind that were present at the beginning or A radioactive nuclide's decay constant is defined as its decay probability per unit of time. The relation between decay constant and half-life time is given asHere represents decay constant and represents half-life time.Insert the value of half-life time into the equation above.The total number of atoms of given radioactive element can be calculated asHere represents total number of atoms, represents Avogadro's number, represents mass and represents molar-mass.Insert the values of mass, molar mass and Avogadro numbe'sr into the equation above.The activity of a radioactive element is given asHere represents activity, represents total number of atoms and represents decay constant.Insert the values of decay constant and number of atoms into the equation above.Activity is