What is the difference between am radio and fm radio?

FM radio gives you more clarity... nearly CD quality.But you can receive stations in a range of 100 km or so.
AM is long range..but voice clarity not that great

a radio is something which receives the signal transmitted by a broadcasting station in the vicinity of the radio set and converts this signal into audible range sound wave.FM radios serve the same purpose with the differences lying in the type of signal they process.e.g. a general radio can process amplitude modulated(AM) wave while an FM radio processes the frequency modulated(FM) signals hence the name FM radio.moreover they differ in sound quality(fidelity),range of reception etc..

FM radio requires line-of-sight to get its signal to your radio. Mountains and high locations are preferred for FM because the higher a radio station can get the FM antenna, the larger the coverage area, and the more likely you'll be able to receive the signal in your car or home. Most Seattle-area FM radio station transmitters are located on West Tiger Mountain and Cougar Mountain