photoelectric effects if you blast a metal with very high-energy light or even a semiconductor you can actually remove electrons from that from that material lecterns literally come right up this Vitalita Derma type of a phenomenon is actually using a lotto I'll a it's used in a lotto different types a scientific devices which we're not going to get into right now by I'm the focus here the work function the work function is the amount of energy required to on I to get an electron to I BP at case was given an electron volts this light has to have an energy greater than the work function to reject an electrometer this crap here shows the frequency at the light and Matt this year showing EM so this is the at the energy of the electrons every minute so you'll notice that on so there's a way to actually measure the energy of the electrons emitted .

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