For a hydrogen-like atom, classify these electron transitions by whether they result in the absorption or emission of light.
n=3 to n=5, n=1 to n=3, n=3 to n=2, n=2 to n=1

Energy must be absorbed to for the electron to transfer from ground state to a much higher energy level. In the same manner, Energy is emitted when the electron is transferred from a higher energy level to a lower energy level. Thus,

n=3 to n=5 à absorb

n=1 to n=3 à absorb

n=3 to n=2 à emit

n=2 to n=1 à emit

practical process described pest part of scientific investigation.

because practical knowledge is powerful then therotical knowledge.