Share to: /   The Chinese make light Work of Payment: The Invention of Paper Money   / Around 650 AD, the emperor of China began to issue paper value tokens for general use.
Answer: No. Mobile phones do not give off sub-atomic (ionizing)  radiation.    Answer: Yes. Mobile phones emit microwave (millimeter to  centimeter range) electro-mag â¦ netic radiation, mostly at frequencies  from 800 to 1800 MHz (1.8 GHz).This is below infrared.nswer: No. Mobile phones do not give off sub-atomic (ionizing)  radiation.    Answer: Yes. Mobile phones emit microwave (millimeter to  centimeter range) electro-mag â¦ netic radiation, mostly at frequencies  from 800 to 1800 MHz (1.8 GHz). This is below infrared.
Many people are familiar with the sound, as it differs markedly from the dial tone, the tone that indicates that the phone line is open and ready to be dialed. In most cases, a busy signal simply indicates that the person being called is on the phone, or that the phone is off the hook. In these instances, the signal indicates that there is no technical obstacle to placing the call, but that the call cannot be completed because the phone is in use.