Question 9(Multiple Choice Worth 2 points)
Which statement best describes an atom?
O Protons and neutrons grouped in a specific pattern
O Protons and electrons spread around randomly
O A group of protons and neutrons that are surrounded by electrons
Aball of eleons and neutrons surrounded by protons

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up