1 Secondary emission: An electron, atom or molecule colliding with the surface of the cathode with enough energy can knock electrons out of the surface. 2  Photoelectric emission: Electrons can also be emitted from the electrodes of certain metals when light of frequency greater than the threshold frequency falls on it.
Best Answer: Do it yourself, often referred to by the acronym DIY, is a term used by various communities that focus on people (called do-it-yourselfers or DIYers) creating or repairing things for themselves without the aid of on-duty, work-stationed paid professionals.
Makey Makey is a toolkit for experimentation based on the guts of a USB keyboard. But instead of connecting the circuit with plastic buttons, you get to choose your own âkeysâ. Use the supplied alligator clips to create an interface using the materials you have in the world around you.