An industrial worker accidentally inhaled a radioisotope with an activity of 0.200 kBq. The substance swallowed has a very long effective half-life and therefore the activity will not change significantly during the workers lifetime. Every decay of the isotope releases 1.12 x 10-14 J of energy into the body and the radioisotope is not eliminated from the body.

Question

Determine the amount of energy absorbed in one year by the worker from this substance

Answer 1

200 kBq of activity is equivalent to 200*10^3 radioactive decays per second. This rate can be assumed to be constant. In one year, there will be

(200*10^3 decays/s)*3600*24*365 s/yr) = 6.3*10^12 decays. Multiply this by 1.12*10^-14 J/decay for total Joules absorbed per year.