Question

The half-life of a radioactive isotope is 6.5h. If there are Initially 48 x 10^32 atoms of this isotope, the number of atoms of this isotope remaining after 26h is
A. 12X10^32
B. 6x10^4
C. 6x10^32
D. 3x10^2
E. 3x10^32 ​

Answer 1

We note that t=24h is four times T1/2=6.5h. Thus, it has reduced by half, four-fold:              (21)4(48×1019)=3.0×1019 .The fraction of the Hg sample remaining as a function of time (measured in days) is plotted below

Answer 2

Explanation:

handbook" - Internet Archive

TABLE OF ISOTOPES Table 1 219 Table II 381 V. GLOSSARY . ... P d = angle in degrees 32 JrN K. INTERNAL RADIATION DOSAGE (1) Biological Half-Life 0.693 (2) ...