Energy of a photon : E = hf The photoelectric effect works like this. If you shine light of high enough energy on to a metal, electrons will be emitted from the metal. Light below a certain threshold frequency, no matter how intense, will not cause any electrons to be emitted.
The Boogie Board Jot 8.5 is an uber-slim slate with a black 8.5â³ screen. The stylus clicks into the opening under the screen. When you use the stylus it writes on the screen in a bright green color. The company claims this board is 50% brighter than their previous Jot model.
The Boogie Board LCD is able to erase the writing on the tablet with just a single touch. It will also flash when the writing has been wiped from the board - It looks really awesome! Another cool aspect of the boogie board LCD tablet is that it comes with 3V watch battery. It is so powerful that it never needs replacing at all. You can literally use this graphics tablet for years without having to worry about diminishing battery life.