Answer:
0.805 or 0.781 depending on the method used.
Explanation:
Data provided
half life ie t1/2= 8days.
No= 50g
t=48days
Nt=?
Method 1
Formula: Nt= No(1/2)^n
where n= number of half lives.
= t/t1/2 = 48/8
=6.
thus Nt= 50(1/2)^6= 0.781
Method 2
Formula: Nt= Noe^-(lambda)t
where lambda= decay constant
= ln2/ t1/2= ln2/ 8 = 0.086.
thus Nt= 50e^-(0.086×48)= 0.805.