Weird high pitched whine from LED light?

I noticed this while watching a movie one day. My N5X was on the charger and I got a Snapchat. Whenever the notification LED pulses, there's a very high pitched whine that the light also seems to emit. Has anyone else noticed this or is this a defect specifically with my phone? I'm relatively young, under 20 to be exact so my ears can still hear frequencies at particularly high ranges.