Question

Expert Q&A Done $^{136}Cs$ (half-life = 13.7 d) decays ($\beta^-$) into $^{136m}Ba$ (half-life = 0.4 s), which decays ($\gamma$) into stable $^{136}Ba$: $^{136}Cs \xrightarrow{\beta^-} \; ^{136m}Ba \xrightarrow{\gamma} \; ^{136}Ba$. 13.7 d 0.4 s Starting with a pure $10^{10}$ Bq sample of $^{136}Cs$ at time $t = 0$, how many atoms of $^{136m}Ba$ decay between time $t_1 = 13.7$ d (exactly) and time $t_2 = 13.7$ d + 5 s (exactly)?

          Expert Q&A
Done
$^{136}Cs$ (half-life = 13.7 d) decays ($\beta^-$) into $^{136m}Ba$
(half-life = 0.4 s), which decays ($\gamma$) into stable $^{136}Ba$:
$^{136}Cs \xrightarrow{\beta^-} \; ^{136m}Ba \xrightarrow{\gamma} \; ^{136}Ba$.
13.7 d                     0.4 s
Starting with a pure $10^{10}$ Bq sample of $^{136}Cs$ at time $t = 0$,
how many atoms of $^{136m}Ba$ decay between time $t_1 = 13.7$ d
(exactly) and time $t_2 = 13.7$ d + 5 s (exactly)?

Expert Q A
Done
^136Cs (half-life = 13.7 d) decays (β^-) into ^136mBa
(half-life = 0.4 s), which decays (γ) into stable ^136Ba:
^136Cs β^- ^136mBa γ ^136Ba.
13.7 d 0.4 s
Starting with a pure 10^10 Bq sample of ^136Cs at time t = 0,
how many atoms of ^136mBa decay between time t1 = 13.7 d
(exactly) and time t2 = 13.7 d + 5 s (exactly)?

Added by Erika J.

Physics: Principles with Applications

Douglas C. Giancoli 7th Edition

Chapter 30

Instant Answer

Solved by Expert Penny Riley

Step 1

We have ¹³⁶Cs (half-life = 13.7 d) decays via β⁻ into ¹³⁶ᵐBa (half-life = 0.4 s), which then decays via γ into stable ¹³⁶Ba. Show more…

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136Cs (half-life = 13.7 d) decays into 136mBa (half-life = 0.4 s), which decays into stable 136Ba: 136Cs -> 136mBa -> 136Ba Starting with a pure 10^10-Bq sample of 136Cs at time t=0, how many atoms of 136mBa decay between time t = 13.7 d (exactly) and time t = 13.7 d + 5 s (exactly)?