Radioactive decay obeys which one of the following law ?
A. N=Noe-λt
B. N=Noeλt
C. N=Noe-λt/2
D. No=N(1+eλt)
A. N=Noe-λt
B. N=Noeλt
C. N=Noe-λt/2
D. No=N(1+eλt)