A silver sphere of radius $1 \mathrm{cm}$ and work function $\text{4.7} \mathrm{eV}$ is suspended from an insulating thread in free-space. It is under continuous illumination of $200 \mathrm{nm}$ wavelength electromagnetic waves. As photoelectrons are emitted, the sphere gets charged and acquires a potential. The maximum number of photoelectrons emitted from the sphere is $\mathrm{A}\times {10}^{\mathrm{Z}}$ (where $1<\mathrm{A}<10$). The value of $\mathrm{Z}$ is