Question

when is light emitted from an atom?
when the nucleus absorbs energy
when the nucleus releases visible light.
when an electron goes from a lower energy orbital to a higher energy orbital.
when a proton goes from a higher energy orbital to a lower energy orbital.
when a proton goes from a lower energy orbital to a higher energy orbital.
when an electron goes from a higher energy orbital to a lower energy orbital.

Explanation:

In atomic physics, electrons in an atom can occupy different energy - level orbitals. When an electron transitions from a higher energy orbital to a lower energy orbital, the excess energy is released in the form of a photon (light). Absorbing energy causes electrons to move to higher energy levels, and protons do not move between energy orbitals in the context of light - emission in atoms.

Answer:

When an electron goes from a higher energy orbital to a lower energy orbital.