Fact 1: Aradio converts electrical energy into vibrations.

Fact 2: Sound, a type of energy, is produced by vibrations and travels in waves.

Given the two facts above, answer the question "A radio converts electrical energy into what?" with the following options: 
- speed
 - pictures
 - light
 - warmth
 - photons
 - engines
 - sound
 - motion


 

       sound  