• # question_answer 8 gms of a radioactive substance is reduced to $0.5\,g$ after 1 hour. The ${{t}_{1/2}}$ of the radioactive substance is                   [DCE 2000] A)            15 min B)            30 min C)            45 min                                      D)            10 min

${{N}_{o}}=8gms,\,$N = 0.5g and t = 1 hr. = 60 min. find ${{t}_{1/2}}$ by $t=\frac{2.303\times {{t}_{1/2}}}{0.693}\log \frac{{{N}_{o}}}{N}$.