A certain minimum energy(E min) is required to eject an electron from a photosensitive surface. Any energy obsorbed beyond this minimum gives kinetic energy to the ejected electron. When 540-nm light falls on a cesium surface, an electron is ejected with a kinetic energy of 6.69 X 10 ^-20 J. When the wavelength is 400 nm, the kinetic energy is 1.96 X 10 ^-19 J.

A) Calculate the minimum energy (E min) for cesium, in joules.

B) Calculate the longest wavelength, in nanometers, that will eject an electron from cesium.