In class, we used small radioactive sources as demonstrations. One of those source is 13 Cs with an activity of 1.85 × 104 decay/sec and emits a gamma ray with energy 662 keV in 95% of all decays. Assume that the source is small and the radiation is emitted uniformly in all directions. The closest student in the room was at a distance of 3.0 m. If the dose rate at a distance of 1.0 m is 0.11 puSv/hour how much dose is the student given during the two hour class period? (a) 1.22 x 10-3 µSv (b) 2.23 x 10-3 µSv (c) 1.22 x 10-2 µSv (d) 2.44 x 10-² µSv (e) 3.37 x 10-2 µSv

In class, we used small radioactive sources as demonstrations. One of those source is 13 Cs with an activity of 1.85 × 104 decay/sec and emits a gamma ray with energy 662 keV in 95% of all decays. Assume that the source is small and the radiation is emitted uniformly in all directions. The closest student in the room was at a distance of 3.0 m. If the dose rate at a distance of 1.0 m is 0.11 puSv/hour how much dose is the student given during the two hour class period? (a) 1.22 x 10-3 µSv (b) 2.23 x 10-3 µSv (c) 1.22 x 10-2 µSv (d) 2.44 x 10-² µSv (e) 3.37 x 10-2 µSv