mobile "lights"
I have seen some light making stickers sold that can be put on your mobile and they emit light when you talk. Am I right that they will lower my chances of getting connected when I am far from the antenna? I mean they must somehow make signal weaker, don;t they?
Why transformers hum?
I have heard two versions. Oxygen has unpaired electrons and it reacts to changing magnetic field. Material that transformer is made of vibrates in changing magnetic field.
Both explanations tell that something vibrates in a magnetic field, but what it is?