well physics involves the study of matter and motion through spacetime, as well as energy and force. So broadly anything has to do with physics.
Light amplification by stimulated emission of radiation (LASER or laser) is a mechanism for emitting electromagnetic radiation, typically light or visible light, via the process of stimulated emission.
The device uses a microphone in the handset to convert the sound waves to electrical signals, which are sent through the telephone network to the other phone, where they are converted back to sound waves by an earphone in the handset.
Physics can be applied to everything pretty much