The retarding potential for having zero photo-electron current:

If two metals $A$ and $B$ are exposed to radiation of wavelength $350 \, nm$. The work functions of metals $A$ and $B$ are $4.8 \, eV$ and $2.2 \, eV$ respectively. Choose the correct option.

$A$ photoelectric surface is illuminated successively by monochromatic light of wavelength $\lambda$ and $\frac{\lambda}{2}$. If the maximum kinetic energy of the emitted photoelectrons in the first case is one-fourth that in the second case,the work function of the surface of the material is ($c=$ speed of light,$h=$ Planck's constant).

$A$ metal plate of area $1 \times 10^{-4} \, m^2$ is illuminated by radiation of intensity $16 \, mW/m^2$. The work function of the metal is $5 \, eV$. The energy of the incident photons is $10 \, eV$ and only $10\%$ of the incident photons produce photoelectrons. The number of emitted photoelectrons per second and their maximum kinetic energy, respectively, will be: $[1 \, eV = 1.6 \times 10^{-19} \, J]$

When light of frequency $8 \times 10^{14} \ Hz$ is incident on a surface,photoelectrons are emitted with a maximum speed of $7 \times 10^5 \ m/s$. The threshold frequency for this surface is ..........

The slope of the graph between the frequency of incident light and the stopping potential for a given surface is: