Does a socket with no plug attached use electricity? What if the attached appliance is turned off?

I see a lot of people leave unused sockets with the switches turned on. Does this use up electricity?





What happens to electricity usage if there is an appliance plugged in, like a kettle, but it isn't being used?|||No electricity is use if nothing is in the socket, On your appliance maybe, if its got some light lighting up showing like time, on or off it will put some electricity.