When a photon of light collides with a metal surface, the number of electrons (if any) coming out is:

Radiation of two photon energies,twice and five times the work function of a metal,are incident successively on the metal surface. The ratio of the maximum velocity of photoelectrons emitted in the two cases is:

Photoelectric emission is observed from a metallic surface for frequencies $v_1$ and $v_2$ of the incident light rays $(v_1 > v_2)$. If the maximum values of kinetic energy of the photoelectrons emitted in the two cases are in the ratio of $1:k$,then the threshold frequency of the metallic surface is

Photoelectric emission takes place from a certain metal at threshold frequency $\nu$. If the radiation of frequency $2\nu$ is incident on the metal plate, the maximum velocity of the emitted photoelectron will be ($m = \text{mass of electron}$, $h = \text{Planck's constant}$)

The work functions of metal $A$ and $B$ are in the ratio $1: 2$. If light of frequency $f$ and $2f$ is incident on surface $A$ and $B$ respectively,then the ratio of the maximum kinetic energies of the emitted photoelectrons is:

$A$ photoelectric cell is connected to a source of variable potential difference. The photoelectric current is plotted against the applied potential difference. The graph with the broken line represents the current for a given frequency and intensity of the incident radiation. If the frequency is increased and the intensity is reduced, which curve now represents the situation?