Question

explain how emission lines are formed.
an atoms electron moves to the nucleus and emits a photon. the wavelength of the photon corresponds to the atoms change in energy.
an atoms electron moves to a higher energy level and emits a photon. the wavelength of the photon corresponds to the electrons change in energy.
an atoms proton moves to an electron orbit and emits a photon. the wavelength of the photon corresponds to the atoms change in energy.
an atoms electron moves to a lower energy level and emits a photon. the wavelength of the photon corresponds to the electrons change in energy.
explain how absorption lines are formed.
an atoms electron moves to a higher energy level by absorbing a photon. the wavelength of the photon corresponds to the electrons change in energy.
an atoms electron moves to the nucleus by absorbing a photon. the wavelength of the photon corresponds to the atoms change in energy.
an atoms proton moves to an electron orbit by absorbing a photon. the wavelength of the photon corresponds to the electrons change in energy.
an atoms electron moves to a lower energy level by absorbing a photon. the wavelength of the photon corresponds to the electrons change in energy.
in what sorts of cosmic objects would you expect to see each?

Explanation:

Emission lines form when an atom's electron moves to a lower energy level and emits a photon. The photon's wavelength corresponds to the electron's energy - change. Absorption lines form when an atom's electron moves to a higher energy level by absorbing a photon, with the photon's wavelength matching the electron's energy - change. Emission lines are seen in hot, glowing objects like stars and nebulae. Absorption lines are seen in cooler gas clouds in front of hot objects or in the atmospheres of stars.

Answer:

1. An atom's electron moves to a lower energy level and emits a photon. The wavelength of the photon corresponds to the electron's change in energy.
2. An atom's electron moves to a higher energy level by absorbing a photon. The wavelength of the photon corresponds to the electron's change in energy.
3. Emission lines: Stars, nebulae. Absorption lines: Cooler gas clouds in front of hot objects, star atmospheres.