Question

Find the minimum kinetic energy (in MeV) in the lab system needed by an alpha particle to cause

the reaction:

7𝑁

14 + 𝛼 → 8𝑂

17 + 1𝐻

1

Given that: m(

14N) = 14.00307 u; m(α) 4.003879 u; m(

1H) = 1.00783 u; m(

17O) = 17.0013 u;

1 𝑢 = 931.5 𝑀𝑒𝑉/𝑐

2

Answer 1

Solution:

$N^{14}+ \alpha \to O^{17}+p$

$Energy=E= \Delta mc^2$

$\Delta m=14.00307+4.003879-1.00783-17.0013=-0.002181$

$E= \Delta mc^2=0.002182 \times931.5 𝑀𝑒𝑉=-2.0316015\;MeV$

So, -2.0316015 MeV is needed by an alpha particle to cause the reaction.