The work functions of tungsten and sodium are $5.06 \ eV$ and $2.53 \ eV$ respectively. If the threshold wavelength for sodium is $5896 \ \mathring{A}$,then the threshold wavelength for tungsten will be .......... $\mathring{A}$.

When light is incident on a surface, photoelectrons are emitted. For photoelectrons:

The retarding potential necessary to stop the emission of photoelectrons,when a target material of work function $1.24 eV$ is irradiated with light of wavelength $4.36 \times 10^{-7} m$ is (in $eV$)

Two radiations of photon energies $1 \; eV$ and $2.5 \; eV$ successively illuminate a photosensitive metallic surface of work function $0.5 \; eV$. The ratio of the maximum speeds of the emitted electrons is

The photoelectric threshold wavelength for a metal surface is $6600 \, \mathring{A}$. The work function for this is:

$A$ photoelectric surface is illuminated successively by monochromatic light of wavelength $\lambda$ and $(\lambda/3)$. If the maximum kinetic energy of the emitted photoelectrons in the second case is $4$ times that in the first case, the work function of the surface of the material is ($h$ = Planck's constant, $c$ = speed of light).