Final answer:
The transition from n=3 to n=1 in a hydrogen atom corresponds to emission of energy.
Step-by-step explanation:
The transition from n=3 to n=1 in a hydrogen atom corresponds to emission of energy. When an electron in a higher energy level (n>1) moves down to a lower energy level (n=1), it releases energy in the form of light or electromagnetic radiation. In this case, the hydrogen atom is emitting energy in the form of photons.