The nucleus of a hydrogen atom is a single proton, which has a radius of about the single electron in a hydrogen atom normally orbits the nucleus at a distance of what is the ratio of the density of the hydrogen nucleus to the density of the complete hydrogen atom?

Which statement correctly describes the relationship between frequency and wavelength?

If a tank filled with water contains a block and the height of the water above point a within the block is 0.8 meter, what is the pressure at point a?

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.