A point source causes photoelectric effect from a small metal plate. Which of the following curves may represent the saturation photocurrent as a function of the distance between the source and the metal?

In a photoelectric experiment, the frequency and intensity of a light source are both doubled. Then consider the following statements. 

(i) The saturation photocurrent remains almost the same. 

(ii) The maximum kinetic energy of the photoelectrons is doubled. 

The work function of a certain metal is $\frac{hc}{{\lambda }_0}$. When a monochromatic light of wavelength $\lambda <{\lambda }_0$ is incident such that the plate gains a total power $P$. If the efficiency of photoelectric emission is $\mathrm{\eta }\%$ and all the emitted photoelectrons are captured by a hollow conducting sphere of radius $R$ already charged to potential $V$, then neglecting any interaction between plate and the sphere, expression of potential of the sphere at time $t$ is,

$(\mathrm{e}=1.6\times {10}^{–19}\mathrm{C})$

The radiation force experienced by body exposed to radiation of intensity $I$, assuming surface of body to be perfectly absorbing is :