For Platinum, the Hall coefficient $($ RH$)$ is $-2\mathrm{.}00$ x $10-11$ m$3/$ C The resutivity is $10\mathrm{.}6\backslash$times $10-2$ Qm and the density is $21\mathrm{.}45$ g$/$cm$3.$ calculate

a$)$ The molality of electrons

b$)$ the number of electrons per atom.

c$)$ If a current of $122$ mA is placed through a sheet of $0\mathrm{.}00503$ cm and $2\mathrm{.}12$ cm in width, what is the value of the Hall potential in a magnetic field of $0\mathrm{.}500$ tesla?