Curious Case of Cable Cord Cylinders

Often mobile or computer chargers come with cables that have a sort of cylindrical formation on one end. While most of us don’t bother to know what’s that or why it’s there, some inquisitive souls found out the logic and purpose of those tube-like extensions.
These are known as ferrite cores that contain magnetic iron oxide in them. Its prime function is to prevent high-frequency electromagnetic waves that interfere with ongoing calls. If we keep the device too close to a speaker, sharp weird noises may start coming without these cylinders. Now we know, right?

