How quickly can an electric switch operate?

[Eltahawy]

Suppose a hypothetical experiment consisting of a lamp that is situated some where on the moon connected to a battery some where on Earth through an ideal conductor(with no losses at all) assume that we turned off the circuit at some time t0 how long it takes for the lamp to illuminate
Or that time it takes depends on which thing ?
Sorry for bad English it's not my native language

 

[phinds]

Electricity travels a bit slower than light. How long does it take light to get from the Earth to the moon?