Electric guitars have pickups (a type of in-built microphone) and need to be plugged into an amplifier (amp) to be heard.
The solid body electric is commonly used in Metal, Rock, Blues and Pop Music. Famous solid body electric guitars are the Fender Stratocaster the Fender Telecaster and the Gibson Les Paul.
The hollow body electric (semi-acoustic) is most commonly used in Jazz and Blues music. A famous hollow body electric guitar is the Gibson 335.