Question Opposite of night light?

[ffranny]

I want to set up a light behind a glass bowl in a small display space in my bathroom. I don't want to wire it, so I'm thinking battery operated.

I only want the display light to go on when the room lights are on -- no reason to have it on when no one's in there, plus battery will last longer.

I can't figure out what search terms to use to find a light that's the opposite of a night light -- it goes on when it senses the room light is on, stays on until the room light goes off.

Is there such a thing, or will my husband have to kluge one together?

Thanks for any suggestions.