Question

what happens when an electron in a hydrogen atom moves from the excited state to the ground state?
a a quantum of energy is absorbed.
b a different electron moves from the ground state to the excited state at the same time.
c a photon is emitted.
d continuous amounts of energy are released.

Explanation:

When an electron in a hydrogen atom transitions from an excited state (higher - energy level) to the ground state (lower - energy level), it loses energy. This energy is released in the form of a photon. Absorption of energy occurs when an electron moves from a lower to a higher energy level. There is no rule that another electron must move simultaneously in the opposite direction, and energy is released in discrete amounts (quanta) not continuously in this context.

Answer:

C. A photon is emitted.