K = (4.14 . 10-15)v – 0 In night vision goggles, light rays cause electrons to be projected from a metal surface. The
above equation relates the kinetic energy in electron volts (EV), K , of emitted electrons to the
frequency in hertz, v, of incident light rays and the work function, $, in eV, of the metallic
surface.
In a particular set of night vision goggles, the electrons emitted must have a kinetic energy of at
least 2.46 eV. If the frequency of incoming light rays is less than 9.60 · 1014 hertz , which of
the following systems of inequalities best models the relationship between the work function, o,
and the light source frequency, v ?