# In photo-electric experiment, if the light is exposed to a metal plate for a long enough interval, does the plate become lighter?

I know from the book that electrons will be kicked out from the metal plate if the light of appropriate wavelength is exposed to the metal plate.

My mental model says if we let the light expose the plate in a long enough interval, the plate will have no electrons anymore. So what happens on the plate? Does it still looks like a plate as the original? Or it become lighter due to loss of electrons?

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Also, unless we are talking about really high energies, only the weakly bound valence electrons will be removed. The work to remove the electron, $W_a$, becomes higher the more electrons have left.