Please help: Tc-99m has a half life of 6.04 hours. The activity of a sample on Monday morning is measured to be 256MBq a. What is the activity at the same time on Tuesday morning? (16.3 MBq) b. What is the activity at the same time on Monday of the following week? (1.08 Bq) c. When will the activity be 187MBq? (2 hours 45 min after measurement)

Question

Please help: Tc-99m has a half life of 6.04 hours. The activity of a sample on Monday morning is measured to be  256MBq  a. What is the activity at the same time on Tuesday morning? (16.3 MBq)  b. What is the activity at the same time on Monday of the following week? (1.08 Bq)  c. When will the activity be 187MBq? (2 hours 45 min after measurement)

anonymous · Answer

Activity is nothing but the rate at which things get decayed....

anonymous · Answer

and the Rate at which species decay is directly proportional to the amount of species leftout

anonymous · Answer

so R = k x N
where R: rate of disintegration
          k: Radioactivity decay constant
          N: no. of species left out (at that instant)

anonymous · Answer

u probably must know,,,,that                    half life=0.693/k............see derivation if in doubt

anonymous · Answer

get k.......

anonymous · Answer

use the eqn R=R' x e^(-kt)

anonymous · Answer

t=24 hrs...___seconds
R': initial Rate (here 256 MBq)
k: calculate using half life
R:this is what u need to find out