Ncert Exercises & Solutions

A set of atoms in an excited state decays

1. in general to any of the states with lower energy

2. into a lower state only when excited by an external electric field

3. all together simultaneously into a lower state

4. to emit photons only when they collide

(1) Hint: The decay can occur in different ways.

A set of atoms in an excited state decays in general to any of the states with lower energy.