When we get into an elevator and the door gets closed, the network range of the phone goes nil and you can’t make or receive any phone calls !
But, have you thought why this happens so ? Well, here is the answer ! Because the lift acts as a Faraday Cage !
What is a Faraday Cage ?
A Faraday cage or Faraday shield is an enclosure formed by conducting material or by a mesh of such material. Such an enclosure blocks external static and non-static electric fields. Faraday cages are named after the English scientist Michael Faraday, who invented them in 1836.
How Does This Affects The Phone Signals ?
Well, Your cell-phone uses electro-static forces to transmit signals through the air. But as there is no charge inside a Faraday Cage (the elevator itself), your cell phone will not be able to send or receive signals !