A point source of energy often follows the inverse square rule. So if I move my projector back twice as far, the image is 1/4 as bright. If I move half the distance closer to the TV, I can hear it 4 times louder. I’m guessing this rule doesn’t work so well for thunder and lightning since it’s more like a line source than a point source. So if lightning strikes a mile from Alice and 2 miles from Bob, is it half as loud and half as bright for Bob?