you place a one-liter substance in a 2-liter bottle and tightly cover the bottle. the substance expands until it completely fills the bottle. what state is the substance in?

so easy. just google the electromagnetic waves and it’ll pop up.

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

hope this ! this is not copied! search it up, it's free of plagiarism!

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.