31) If the energy of a photon corresponding to a wave length of 6000?A⁰?is 3.32??10¹⁹?joule, the photon energy for a wavelength of 4000?A⁰

32) The work function for aluminium surface is 4.2 eV. The cutoff wavelength for the photo electric effect for the surface is

33) The work function of a photoelectric material is 3.32 eV. The threshold frequency will be equal to

34) Light of wavelength 4000?A⁰?is incident on a metal plate whose work function is 2 eV. The maximum kinetic energy of the emitted photoelectrons would be

35) Given h = 6.6??10^?34?joule sec, the momentum of each photon in a given radiation is 3.3??10^?29?kg metre/sec. The frequency of radiation is