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# The half-life of technetium99 is 60 hours How much of a 50 mg sample will remain after 24 hours

### The half-life of technetium99 is 60 hours How much of a 50 mg sample will remain after 24 hours

The half-life of technetium-99 is 6.0 hours.  How much of a 50.0 mg sample will remain after 24 hours?

A)25.0 mgD)3.12 mg

B)12.5 mgE)none of the sample will remain

C)6.25 mg

52.              The half-life of technetium-99 is 6.0 hours.  How much of a 25.0 mg sample will remain after 24 hours?

A)  25.0 mg    B)  12.5 mg    C)  6.25 mg    D)  3.12 mg    E)  1.56 mg

53.              The half-life of iodine-123 is 13.3 hours.  How much of a 25.0 mg sample will remain after 39.9 hours?

A)  25.0 mg    B)  12.5 mg    C)  6.25 mg    D)  3.12 mg    E)  1.56 mg

54.              The half-life of iodine-123 is 13.3 hours.  How much of a 50.0 mg sample will remain after 39.9 hours?

A)  50.0 mg    B)  25.0 mg    C)  12.5 mg    D)  6.25 mg    E)  3.12 mg

55.              The half-life of iodine-131 is 8.1 days.  How much of a 75.0 mg sample will remain after 24.3 days?

A)  75.0 mg    B)  37.5 mg    C)  18.8 mg    D)  9.38 mg    E)  4.68 mg

56.              The half-life of iodine-131 is 8.1 days.  How much of a 45.0 mg sample will remain after 24.3 days?

A)  2.81 mg    B)  5.62 mg    C)  11.2 mg    D)  22.5 mg    E)  45.0 mg

57.              Phosphorus-32 has a half-life of 14 days.  What fraction of a sample of this isotope will remain after 6 weeks?

A)  1/2    B)  1/4    C)  1/3    D)  1/8    E)  1/16

58.              Strontium-90 has a half-life of 28 years.  How long will it take for 75% of the isotope to decay?

A)  28 years    B)  14 years    C)  42 years    D)  56 years    E)  84 years

59.              Iridium-192 has a half-life of 74 days.  How long will it take for 75% of the isotope to decay?

A)  74 days    B)  111 days    C)  37 days    D)  185 days    E)  148 days

60.              Iridium-192 has a half-life of 74 days.  What fraction of a sample of this isotope will remain after 222 days?

A)  1/2    B)  1/4    C)  1/3    D)  1/8    E)  1/16

abhinav behal 15-Feb-2020