Your wife is holding a mobile phone which contains many songs/videos in song/video formats such as mp3 or avi.
In dictionaries, "turn on/ off" is often used for machines.
to make a machine or piece of electrical equipment such as a television, engine, light etc start operating by pushing a button, turning a key etc
Eg, "Jake turned on his computer and checked his mail."
The dictionary says "by pushing a button". We also push a button on an app, on a mobiephone for example, to turn on a song / video.
Is it idiomatic to say "could you turn the songs/ videos on"?
It seems that people say "play", "could you play the song/video?". But I am not sure.