Silly question: can you hear sounds from unlikely sources (see details)?

I used to be able to hear a muted TV. It would emit this quiet, high-pitched whine. I can’t hear it anymore, and I don’t know if that’s because of a change in my hearing or a difference with our newer flat-screen TV.

An orange light comes on my Nintendo DS when it is charging, and that light is SO LOUD. It makes a very high-pitched noise that will actually keep me awake.

Can you hear noises from things that don’t seem like they should make noise?