I was recently given a physics lab and it's very hard for me to complete. We were shown a demonstration in which some unknown object was in a "black box." There was a wire leading from the box that was plugged in, thus the object was charged. A light bulb was led around the box. Then, at the top of the box, the bulb (with wires or some magnetic base maybe on the bottom?) lit when it reached the top of the box. The farther the lightbulb got from the box, the dimmer it became. I have a few ideas, but can't seem to come up with a working hypothesis. I think the object might be a transformer, some sort of tesla coil, or maybe some sort of broadcast-type object which can transmit electricity. So far, nothing I have come up with is capable of just transmitting a small charge to a small lightbulb through the air.