Physics - Fizik

A mobile phone sends and receives messages by radio waves. The radio waves travel to and from a tranceiver (transmitter/receiver) station which connect the call into the standard telephone network. Countries are divided up into different areas, called cells, and each cell has its own tranceiver station. In an areas where a lot of people live, there are many small cells because there likely to be many people using mobile phones. In sparsely populated areas populated areas, the cells are larger.

Inside a mobile phone

A "mobile" is a low-power radio transmitter-receiver. It has mouthpiece to change sound waves into electrical signals (like a microphone), and an earpiece to change electrical signals into sound waves (like a loudspeaker). The transmitter-receiver only needs to send and pick up waves from the nearest cell tower, which is usually just a few kilometres away. However hulls or tall buildings may block the radio signals. also, in areas where the cell towers are farther apart, the signals may be too weak to travel to and from the phone.