1 Use degaussing mobile phone case or protective film, and attach magnets to the body. He'll check what you put on your cell phone.

Set electromagnetic waves in a hidden place in the classroom … that is, Oster experiment …

3 The materials that cannot be detected by the metal detector are as follows

titanium

Pottery and porcelain

plastic

carbon fiber

Tin foil can shield the signal sent by mobile phone.

If the mobile phone is wrapped in tin foil and can't send and receive, it should be able to escape the monitoring of the radio monitoring car (pay attention to the time when using the mobile phone, and it will be locked after a certain time limit, just like the plot in the movie).

I am only responsible for answering all other questions that have nothing to do with me.