Question

Suppose you look at a spectrum of visible light by looking through a prism or diffraction grating. How can you decide whether it is an emission line spectrum or an absorption line spectrum?

A) An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background.
B) An emission line spectrum consists of a long bright line, while an absorption line spectrum consists of a long dark line.
C) The only way to decide is to make a graph of the intensity of the light at every wavelength, and then analyze the graph carefully.
D) The emission line spectrum is produced by electrons jumping up in energy level, while the absorption line spectrum is produced by electrons jumping down in energy level.

Answer 1

To distinguish between an emission and absorption line spectrum, observe the light through a prism. Emission spectra have bright lines on dark backgrounds, indicating light emitted by electrons falling to lower energy levels. Absorption spectra have dark lines on a rainbow background, where light is absorbed as electrons rise to higher energy levels.

Step-by-step explanation:

To determine whether it is an emission line spectrum or an absorption line spectrum, you can look at the characteristics of the light through a prism or diffraction grating. An emission line spectrum consists of bright lines on a dark background. This situation occurs because the gas is emitting light at specific wavelengths where the electrons jump down to a lower energy level, releasing light. On the other hand, an absorption line spectrum shows dark lines against a continuous rainbow background. This happens because the gas absorbs light at specific wavelengths, correlating with the energy needed for electrons to jump up to a higher energy level, removing light from the spectrum.

The correct answer to the question is A) An emission line spectrum consists of bright lines on a dark background, while an absorption line spectrum consists of dark lines on a rainbow background. Option D is incorrect because it confuses the concept of electrons jumping up or down with the production of the spectra themselves when it's the absence or presence of light at certain wavelengths that actually defines these spectra.