Base on my research, within 2 hours you have a number of atoms which remain.
N= N0*2^(-t/6.020 = N= N0*2^-0.33223= 07943 N0
So, the number of atoms that are being disintegrated is N0-N=N0*(1-0.79430)=0.2057 N0
It must be equal to 15 mCi = 15*3.7*10^7= 5.55*10^8 atoms
N0= 5.55*10*8/0.2057 = 2.698*10^9 atoms
Therefore, 2.698*10^9 atoms is the number of N0
Answer:
As a boy, Sir Isaac Newton was fascinated by a Windmill.
A drawing of a Windmill, which many believe to have been sketched by the young Newton over three an half centuries ago was discovered in his childhood home on a wall.
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