See explanation below.
Work Step by Step
The rate of decay per gram of radioactive sample is its specific activity. Specific activity can be calculated by knowing the number of particles emitted per second and from the mass of sample. 1 Ci is 3.70x10^10 dps Specific activity: ((4.13x10^8 days/3600 sec)/2.6g)(1 Ci/3.70x10^10 dps)= 1.2 x 10^-6 Ci/g