Why does it sometimes seem instant and sometimes it seems to take time for something to work? For example, if I leave my hoover switched on and plug it in, it seems to start immediately, but when I switch the plug off for my tv the stand by light takes a few seconds to go off?
Edit: thanks for the explanation guys, seems like the answer I was looking for was some appliances use capacitors.
In: Physics
Electricity works because charged electrons are made to move by the electromagnetic field, and then pass on that movement energy to other things. A couple of answers mention electrons ‘bumping into each other’ to move down wires, which is incorrect.
Imagine you have a pool table with balls (not touching) on the surface, and you tip up one end of the table. The balls will start to roll down, all at the same time (in fact there is an imperceptible delay in moving those at the far end, which you could imagine seeing if the table was rubbery).
This is like what turning on a switch does for electrons. The electrons don’t travel near the speed of light, but the change in the electric field which moves them (tipping up the table) does.
As other answers have suggested, you are thinking about capacitors, that store charge, taking some time to drain once a device is turned off. This can sometimes happen quite slowly due to the resistance of components, like if the pool table above was sticky.
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