electron move aur vibrate? if move then all free electrons reduses to zero if conducting wire is grounded.
if vibrate then how electrons travel in vacuum in photocell when they emitted from cathode.
It is not quite as simple as you imagine. Electrons behave like particles and they also behave like waves. Do some reading on the Heisenberg Uncertainty Principle. That is a piece of quantum mechanics that is accessible without going into higher mathematics.
In free vacuum electrons act much more like particles, it is photons that are both. When electrons are orbiting their atoms Heisenberg Uncertainty Principle kicks in with a vengeance. You can know the speed of the electron, or it's position, but not both, and the act of measuring changes what you were measuring. This is very much the realm of quantum physics.
The only time atoms/electrons don't move is absolute zero (temperature), where all vibration stops. This is a theoretical state, you can get close but never achieve it, much like the speed of light. I'm not sure, but I believe you can have a current flow at near absolute, but it could raise the temperature (since temperature is basically a measurement of the vibration of the atoms).
So in general electrons are always moving. In metals the outer layer is not tightly bound, so they float between atoms in a random movement. This is why metals are good conductors.
In vacuum tubes (aka valves) electrons go ballistic, flying in the vacuum between the cathode and the anode (and through the gate) like little bullets.