Question $1$

A student designed a shield that consists of two layers $($layer $1$ is aluminum and layer $2$ is a $1\mathrm{.}5m\frac{g}{c}{m}^2$ mica absorber$).$ The shield was placed $2cm($of air$)$ in front of the beta emitter. A counter was placed immediately behind the mica $($no other medium is between the counter and mica$).$ The student determined the range of the beta particle in aluminum to be $0\mathrm{.}12mm.$

Calculate;

i$)$ the total range of the beta particle

ii$)$ the energy of the beta particle