Starting with a sample of pure ${}^{66}\mathrm{Cu}$, $7/8$ of it decays into Zn in 15 minutes. The corresponding half-life is (1) 10 minutes (2) 15 minutes (3) 5 minutes (4) $7\frac{1}{2}$ minutes
Starting with a sample of pure ${}^{66}\mathrm{Cu}$, $7/8$ of it decays into Zn in 15 minutes. The corresponding half-life is\\
(1) 10 minutes\\
(2) 15 minutes\\
(3) 5 minutes\\
(4) $7\frac{1}{2}$ minutes