Cesium is used extensively in photocells and in television cameras because it has the lowest ionization energy of all the stable elements.

a what is the maximum kinetic energy of a photoelectron ejected from cesium by  nm light? Note that if the wavelength become photo electrons of the light used to irradiate the cesium surface becomes longer than nm no photo electrons are emitted. the answer is xJ but I cant figure out what I did wrong

$\mathrm{<font><font><font><font>(</font></font></font></font>}$b use the rest mass of the electron, xkg to calculate the velocity of the photoelectron in a