Question

A set of atoms in an excited state decays

• A. in general to any of the states with lower energy
• B. into a lower state only when excited by an external electric field
• C. all together simultaneously into a lower state
• D. to emit photons only when they collide

Answer 1

Answer: (A)

A set of atoms in an excited state decays in general to any of the states with lower energy which is more stable than the excited state.