Strange noise in headphones. Because of what could it be?

Question

laptops

Good day. I am the owner of a Toshiba laptop (I don’t think the model is important, but I’ll write) C660-1PE. I noticed that if the laptop is connected to the network ( 220 V | 50 Hz ), noise is heard in the right earpiece, like "zzzzzz", but with a different "shade". At the same time, if you put your finger (and any part of the body) on the connected USB flash drive (metal), then the noise stops. If you disconnect the laptop from the network, the noise also stops. Please explain what it is, how to fight and is it harmful?

Answer 1

If the sound frequency is 50 Hz, then it looks like a problem with the wiring in the house (the "zero" is broken somewhere). If so, be careful! In an unfortunate set of circumstances, if you take the flash drive with one hand and the battery or a water pipe with the other, you can get a sickly electric shock. Check for "hum" in other buildings.
If the sound is of a higher frequency, then the problem is somewhere in the power supply circuits of the laptop, perhaps in the power supply itself (non-native power supplies often sin this way, especially cheap Chinese ones). Then first check with another power supply.

Answer 2

the power supply is broken) and pickups are spit in the return line. More precisely, an electrician will tell you). I'm having a hard time with this