The work function of a metal is 4.2eV. If the radiation of 2000Å falls on the metal, find the kinetic energy of the metal

The work function of a metal is 4.2eV. If the radiation of 2000Å fall

1.	The work function of a metal is 4.2eV. If the radiation of 2000Å falls on the metal, find the kinetic energy of the metal
Answer» Solution :`"WORK FUNCTION "E_(0)=hv_(0)=4.2eV` `=4.2xx1.602xx10^(-19)J=6.7284xx10^(-19)J` `"Energy (E) is given as "` `E=hv=(hc)/(LAMBDA)=(6.625xx10^(-34)Jxx3.0xx10^(8)ms^(-1))/(2000xx10^(-10)m)` `"Threshold energy, "E_(0)=6.7284xx10^(-19)J` `"KINETIC energy, "KE=E-E_(0)` `=[9.939xx10^(-19)J-6.728xx10^(-19)J]` `=3.211xx10^(-19)J`