A sample of radioactive material A, that has an activity of 10m Ci(l Ci=3.7 10^{10}decays/s), has twice the number of nuclei as another sample of a different radioactive maternal B which has an activity of 20mCi. The correct choice for hall-lives of A and B an would then be respectively:

a. |
20 days and 5 days |
b. |
20 days and 10 days |

c. |
5 days and 10 days |
d. |
10days and 40days |

A sample of radioactive material A, that has an activity of 10m Ci(l Ci=3.7 10^{10}decays/s), has twice the number of nuclei as another sample of a different radioactive maternal B which has an activity of 20mCi. The correct choice for hall-lives of A and B an would then be respectively:

a. |
20 days and 5 days |
b. |
20 days and 10 days |

c. |
5 days and 10 days |
d. |
10days and 40days |

1 Answer - 5876 Votes

3537

Activity A= N

For A 10=(2N_{0}) _{A}

For B 20=N_{0} _{B}

_{B}=4 _{A} (T_{1/2})_{A}=4(T_{1/2})_{B}