Two incident radiations having energies two times and ten times of the work function of a metal surface,produce photoelectric effect. The ratio of maximum velocities of emitted photoelectrons respectively is

If ultraviolet radiation of $6.2 eV$ falls on an aluminium surface,then the kinetic energy of the fastest emitted electron is (work-function $= 4.2 eV$)

When photons of energy $hv$ fall on a metal plate of work function $W_0$,photoelectrons of maximum kinetic energy $K$ are ejected. If the frequency of the radiation is doubled,the maximum kinetic energy of the ejected photoelectrons will be

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

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 ..........

In a photoelectric experiment,the potential difference $V$ that must be maintained between the illuminated surface and the collector so as just to prevent any electron from reaching the collector is determined for different frequencies $f$ of the incident illumination. The graph obtained is shown. The maximum kinetic energy of the electrons emitted at frequency $f_1$ is