How does an electric guitar work?  How does it pick up the sounds from the strings?
An electric guitar is a guitar that uses one or more pickups to convert the vibration of its strings into electrical signals, i used to be really good at it
Did you only play electric, or did you play an acoustic guitar as well?
both but really enjoyed the electric more, The pickup used to sense the vibration generally uses electromagnetic induction to do so
How does moving one finger along the neck of the guitar, change the pitch of the string?
the pressure on the string changes making the sound different
Were you good enough to tune a guitar by ear, or did you need a tuner?
for a time i learned to do it by ear, The tone of an acoustic guitar is produced by the strings' vibration