In flame photometry, which color corresponds to barium emission?

• A. Green
• B. Red
• C. Blue
• D. Yellow

Answer: (A)

In flame photometry, light emitted by excited atoms in the flame is specific to each element, so the color you see serves as a fingerprint for that element. Barium produces a distinct green light when it emits photons after being excited in the flame. That green emission is the signal used to identify and quantify barium, because the intensity of the green light correlates with how much barium is present. Knowing that barium appears green helps distinguish it from other elements, which show different colors in the flame. So the green color is the indicator of barium emission.