Two streams of photons,possessing energies equal to twice and ten times the work function of a metal,are incident on the metal surface successively. The ratio of the maximum velocities of the photoelectrons emitted in the two respective cases is $x:y$. The value of $x$ is ...... .

The photoelectric threshold frequency of a metal is $v$. When light of frequency $4v$ is incident on the metal,the maximum kinetic energy of the emitted photoelectrons is

Two identical photo-cathodes receive light of frequencies $f_1$ and $f_2$. If the velocities of the photo-electrons (of mass $m$) coming out are $v_1$ and $v_2$ respectively,then:

When photons of wavelength $\lambda_1$ are incident on an isolated sphere,the corresponding stopping potential is found to be $V$. When photons of wavelength $\lambda_2$ are used,the corresponding stopping potential is thrice that of the above value. If light of wavelength $\lambda_3$ is used,then find the stopping potential for this case.

$A$ photon incident on a metal of work function $2 \text{ eV}$ produces photoelectrons of maximum kinetic energy of $2 \text{ eV}$. The wavelength associated with the photon is: (in $\text{ Å}$)

The work function of a surface of a photosensitive material is $6.2\, eV$. The wavelength of the incident radiation for which the stopping potential is $5\, V$ lies in the