The photoelectric cut-off voltage in a certain experiment is $1.5 \; V$. What is the maximum kinetic energy of photoelectrons emitted?

The threshold frequency for a photosensitive metal is $3.3 \times 10^{14} \text{ Hz}$. If light of frequency $8.20 \times 10^{14} \text{ Hz}$ is incident on this metal,the cut-off voltage for the photoelectron emission is nearly ............ $V$.

The work function of sodium is $2.3 eV$. The threshold wavelength of sodium will be ........... $\mathring A $

Ultraviolet light of wavelength $300 \ nm$ and intensity $1.0 \ W/m^2$ falls on the surface of a photosensitive material. If $1\%$ of the incident photons produce photoelectrons,then the number of photoelectrons emitted from an area of $1.0 \ cm^2$ of the surface is nearly

$A$ photon of $5.5 \ eV$ energy falls on the surface of a metal,emitting photoelectrons with a maximum kinetic energy of $4.0 \ eV$. The stopping voltage required for these electrons is .......... $V$.

When photons are incident on a photosensitive material of work function $1.5 \text{ eV}$,the maximum velocity of the emitted photoelectrons is $8 \times 10^5 \text{ m/s}$. The stopping potential of the photoelectrons is (Mass of the electron $= 9 \times 10^{-31} \text{ kg}$ and charge of the electron $= 1.6 \times 10^{-19} \text{ C}$) (in $V$)