The solution to this problem is A.
Answer:
24 days
Step-by-step explanation:
Let the permissible time be Ro
Let the initial activity be R= 8Ro
From;
0.693/t1/2 × t= 2.303 log R/Ro
Half life of the radionuclide= t1/2 = 8 days.
Hence;
0.693/8 × t = 2.303 log 8
t= 2.1/0.087
t= 24 days
Option A because it’s the most effective
By Green's theorem,
where is the disk with as its boundary. The integral is simply -6 times the area of the disk , which has radius √6, and hence area 6π, so the value of the integral is -36π.