The threshold frequency for a photosensitive metal is 3.3 $$ \times $$ 10¹⁴ Hz. If light of frequency 8.2 $$ \times $$ 10¹⁴ Hz is incident on this metal, the cut- off voltage for the photoelectron emission is nearly

In photoelectric emission process from a metal of work function 1.8 eV, the kinetic energy of most energetic electrons is 0.5 eV. The corresponding stopping potential is

Electrons used in an electron microscope are accelerated by a voltage of 25 kV. If the voltage is increased to 100 kV then the de-Broglie wavelength associated with the electrons would

Light of two different frequencies whose photons have energies 1 eV and 2.5 eV respectively illuminate a metallic surface whose work function is 0.5 eV successively. Ratio of maximum speeds of emitted electrons will be