The kinetic energy of the free electron at the point of collision is higher if the atom is closer to the source of electrons
A. True
B. False

The only way to emit IR photons is if there are empty electronic energy levels really close to the ground state (lowest energy level).
A. True
B. False

When atomic electrons are excited to a higher level, they always return to their lowest energy level by jumping down one level at a time.
A. True
B. False