The graph between maximum kinetic energy and intensity of light in photoelectric effect is plotted. Out of the four graphs $A, B, C, D$ shown in the figure, the correct graph is

In a photoelectric experiment, it is found that stopping potential for a given metal is to be $V_o$ volt in presence of wavelength ${\lambda }_o$. When radiation of wavelength  $2{\lambda }_o$ is used with the same metal then what will be the stopping potential (in Volt )?

A graph is plotted between maximum kinetic energy $\left(E_{\mathit{k}}\right)$ of electrons with frequency of incident photon $\left(\nu \right)$ in photoelectric effect. The slope of the curve will be,