\(= \,\,\,\,{2^{ - t/{T_H}}}\,\, = \,\,\,{2^{ - 20/40}}\,\, = \,\,\frac{1}{{\sqrt 2 }}\)
\(\therefore\) ક્ષય પામેલોભાગ \( = \,\,1\,\, - \,\,\,\frac{N}{{{N_0}}}\,\,\)
\(= \,\,1\,\, - \,\,\frac{1}{{\sqrt 2 }}\,\, = \,\,\frac{{\sqrt 2 - 1}}{{\sqrt 2 }}\)
$A \to B + {\;_2}H{e^4}$
$B \to C + \;2{e^ - }$
તો ...