13.c 14.c 15.d 16.c Pls tell 13,14,15,16 its urgent

Dear Student,

13. O₁₉ decays by nuclear decay of a neutron to form a beta particle and forming daughter nucleus of fluorine. Thus the mass in R.H.S is short by just one neutron, thus after nuclear decay comparable to one half life, the mass lost should be not be very great, but it should also be not equal to initial mass, thus it will be little less than 1 Kg. ( option c ) 

14. 

$$\begin{gathered} N=N_0{e}^{-\lambda t} \\ where \lambda =\frac{\ln 2}{t_{{\displaystyle \frac{1}{2}}}} \\ for t=t_{\frac{1}{2}} we have N=\frac{N_0}{2} i.e if N_0=100, N=50 after 1 half life \end{gathered}$$


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