Hey i need with this question. how do microwaves penetrate?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?

During cooling, the kinetic energy of the molecules falls. why does this happen? a. the motion of the molecules increases. b. the motion of the molecules slows down. c. the van der waals forces between molecules decrease d. the forces of attraction between the molecules are overcome.

How is an electron dot structure used to represent a covalent bond?