CD-ROMs use the same laser technology as your audio CD player. As a matter of fact, a PC equipped with a CD-ROM drive can play an audio CD. However where an audio CD contains only music, a CD-ROM disk contains software, data, video, and music.
Like the audio CD player, the CD-ROM drive has a laser beam which reflects off the bottom surface of the disk to read or "play" the information from the disk. All information is stored on the bottom surface of the CD-ROM disk.
Most CD-ROM drives have audio jacks in the front of the drive. You can plug in your headphones and listen to the music when you are playing an audio CD. However, you can not plug in speakers because they would need an amplifier. Headphones do not need an amplifier.
Most people purchase a sound card and connect their CD-ROM drive to this card. You can then connect speakers to the sound card and play you audio CD.