Fastest
(Known as the fast lane)
Solution :
The nuclear reaction for boron is given as :

And the reaction for Cadmium is :
![$^{113}\textrm{Cd}_48 + ^{1}\textrm{n}_0 \rightarrow ^{114}\textrm{Cd}_48 + \gamma [5 \ \textrm{MeV}]$](https://tex.z-dn.net/?f=%24%5E%7B113%7D%5Ctextrm%7BCd%7D_48%20%2B%20%5E%7B1%7D%5Ctextrm%7Bn%7D_0%20%5Crightarrow%20%5E%7B114%7D%5Ctextrm%7BCd%7D_48%20%2B%20%5Cgamma%20%5B5%20%5C%20%5Ctextrm%7BMeV%7D%5D%24)
We know that it is easier that to shield or stop an alpha particle (i.e. He nucli) as they can be stopped or obstructed by only a few centimetres of the material. However, the gamma rays ( γ ) can penetrate through the material to a greater distance. Therefore, we can choose the first one.
Gases, liquids and solids are all made up of atoms, molecules, and/or ions, but the behaviors of these particles differ in the three phases. ... gas are well separated with no regular arrangement. liquid are close together with no regular arrangement. solid are tightly packed, usually in a regular pattern.