Multiple Choice
The half-life of a radioactive isotope is 140 days.In how many days does the decay rate of a sample of this isotope decrease to one fourth its initial decay rate?
A) 35 days
B) 70 days
C) 105 days
D) 210 days
E) 280 days
Correct Answer:
Verified
Correct Answer:
Verified
Q57: The half-life of a radioactive substance is:<br>A)half
Q58: Bromine, with atomic mass 79.942 u, is
Q59: A beta particle is:<br>A)a helium nucleus<br>B)an electron
Q60: The <sup>66</sup>Cu (Z = 29)produced in a
Q61: Radioactive <sup>90</sup>Sr has a half-life of 30
Q63: Magic nucleon numbers are associated with:<br>A)nuclei that
Q64: Beta particles from various radioactive sources all
Q65: The energies of electrons emitted in
Q66: Let Z denote the atomic number and
Q67: Iron has atomic number 26.Naturally mined iron