Visible light cannot eject photoelectrons from copper surface, whose work function is 4.4 eV. Why? Prove it mathematically.

Visible light cannot eject photo electrons from copper metal, whose work function is 4.4 e V. Why? Prove it mathematically.

Radiation of wavelength 180 nm ejects photoelectrons from a plate whose work funcion is 2.0 eV. If uniform magnetic field of flux density 5.0 xx 10^-5 T is applied parallel to the plate, what should be the radius of the path followed by electrons ejected normally from the plate with maximum energy.

Calculate the threshold wavelength of photons, which can emit photoelectrons from cesium. Given that work function of cesium=1.8 eV.

A radiation of 5000 overset @ A is incident on metal surface whose work- function is 1.2 eV. find out the value of stopping potential.

Light of wavelength 500 nm falls on a metal whose work function is 1.9 eV. find the energy of the Photon in eV