Line absorbtion and Emission spectra

Question 1

How do you get emission spectra?

Answer 1

• Electrons are accelerated through a gas
• Electrons give some of their energy to an electron in the gas atoms
• The electrons in the atom are excited to a higher (quantum) energy level
• When the electrons moves back to a lower energy level they release the energy as a photon of a specific frequency

Question 2

How do you get absorption spectra

Answer 2

• Photons of all frequencies pass through a gas
• Photons of specific frequencies give all of their energy to an electron in an atom
• The electron in the atom is excited to a higher (quantum) energy level
• All other photons cannot interact with the electrons and go straight through the gas
• When the electron moves back to a lower energy level it releases the energy as a photon of a specific frequency in a random direction, reducing the intensity in the original direction