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

The $\frac{e}{m}$ of electron is $1.76\times {10}^{11}{\mathrm{ckg}}^{-1}$ and stopping potential is $0.71 \mathrm{V}$, then the maximum velocity of the photoelectrons is :

This question has statement-$1$ and statement $-2$ of the four choices given after the statements, choose the one that best describes the two statements. A metallic surface is irradiated by a monochromatic light of frequency $v>v_0$ (the threshold frequency). The maximum kinetic energy and stopping potential are ${\mathrm{K}}_{\max }$ and ${\mathrm{V}}_0$ respectively. If the frequency incident on the surface is doubled, both the ${\mathrm{K}}_{max}$ and ${\mathrm{V}}_0$ are doubled.

Statement-II The maximum kinetic energy and the stopping potential of photoelectrons emitted from a surface are linearly dependent on the frequency of incident light:

Photoelectric effect experiments are performed using three different metal plates p, q and r having work functions ${\mathrm{\varphi }}_{\mathrm{p}}=2.0\mathrm{eV},{\mathrm{\varphi }}_{\mathrm{a}}=2.5\mathrm{eV}$ and ${\mathrm{\varphi }}_{\mathrm{r}}=3.0\mathrm{eV}$ respectively, A light beam containing wavelength of $550\mathrm{nm}, 450\mathrm{nm}$ and $350\mathrm{nm}$ with equal intensities illuminates each of the plates. The correct $\mathrm{I}-\mathrm{V}$ graph for the experiment is, see Fig. $19.15$