The work functions for metals A, B and C are respectively 1.92 eV, 2.0 eV and 5 eV. According to Einstein's equation the metals which will emit photoelectrons for a radiation of wavelength 4100 $$\mathop A\limits^ \circ $$ is/are

A photosensitive metallic surface has work function, h$$\upsilon $$₀. If photons of energy $$2h{\upsilon _0}$$ fall on this surface, the electrons come out with a maximum velocity of 4 $$ \times $$ 10⁶ m/s. When the photon energy is increased to 5 h$$\upsilon $$₀, then maximum velocity of photoelectrons will be

According to Einstein's photoelectric equation, the graph between the kinetic energy of photoelectrons ejected and the frequency of incident radiation is

J.J. Thomson's cathode-ray tube experiment demonstrated that