What are photo electrons?

The longest wavelength that can eject photo electrons from pt is 1950overset@A . Calculate its work function in electron volt.

The photo electrons emitted from the surface of sodium metal are

Two identical photo-cathodes receive light of frequencies v and v/2. If the velocities of the photo electrons (of mass m ) coming out are respectively V_1 and V_2 then

The work function of metal is 1 eV . Light of wavelength 3000 Å is incident on this metal surface . The velocity of emitted photo - electrons will be

An increase in the intensity of incident light does not change the maximum velocity of the emitted photo electrons.Why ?

Photons of energy 6 eV are incident on a metal surface whose work function is 4 eV . The minimum kinetic energy of the emitted photo - electrons will be

A metal surface of work function 1.07 eV is irradiated with light of wavelength 332 nm . The retarding potential required to stop the escape of photo - electrons is