The Quantum Barcode: Emission and Absorption Lines Quiz

If a solid object is heated until it glows, the atoms are packed so tightly that their energy levels blend together; if they blend together, then the object emits light at every possible color, creating a continuous spectrum.

If electrons in an atom move from one discrete energy state to another, then they must either absorb or emit a photon with an exact amount of energy; if that energy corresponds to a specific wavelength, then a line is formed in the spectrum.

If a thin, hot gas has excited electrons falling to lower energy states, then those electrons release energy as light; if this light is only at specific wavelengths, then it appears as bright lines against the darkness.

If a hot, dense object produces a continuous rainbow of light, and if that light passes through a cooler gas, then the gas atoms will soak up specific photons; if those photons are removed, then dark gaps appear in the rainbow.

If we are analyzing the component wavelengths of light to determine chemical properties, then the field of science is spectroscopy.

If the source is a thin gas where atoms are excited by heat or electricity, then those atoms will emit light as they return to ground state; if light is emitted rather than blocked, it is an emission spectrum.

If an atom "absorbs" a photon from a passing light source, then it has gained energy; if it gains energy, then an electron must jump to a higher, more distant orbital to accommodate that energy increase.

If different elements in the Sun's outer layers absorb specific wavelengths of light from the core, then those missing lines act as a "chemical signature"; if we match these to lab data, we can identify elements like Helium.

If every element has a different number of protons and a unique electron configuration, then the energy gaps between levels are different for every element; if the gaps are unique, then the resulting pattern of light lines is also unique.

If an object is so dense that its energy levels overlap and it emits light at all possible wavelengths, then it produces a solid band of color known as a continuous spectrum.

If we want to see absorption, we must have a background rainbow to start with (source), a medium to remove certain colors (gas), and a tool to split the light (prism/grating) to see the missing parts.

If the background is dark and the only visible features are bright, colored lines produced by the gas itself, then the gas is emitting light; therefore, it is an emission spectrum.

If an electron falls to a lower energy state, it must release its excess energy; if that energy is released as light, then a bright emission line is produced rather than a dark absorption line.

If historical records attribute the discovery of hundreds of dark lines in the Sun's light to a specific German optician, then that individual is Fraunhofer.

If a specific jump (e.g., Level 2 to 3) requires 2.0 electron-volts to go up, then it must release exactly 2.0 electron-volts to go down; if the energy is the same, then the wavelength of the light absorbed or emitted must be identical.

If we see which lines are present, how wide they are, and if they are shifted left or right, then we can calculate composition, heat, speed, and pressure; biological surface features cannot be seen via spectra.

If an object moves away from the observer, its light waves are stretched (Doppler Effect); if the wavelengths increase, then every line in the spectrum will shift toward the longer-wavelength "red" end.

If energy in an atom is "quantized," then an electron must be at one specific level or another; if it cannot exist in between, then the jump is instantaneous, which is why spectral lines are so narrow and specific.

If an electron is as close to the nucleus as possible and has the minimum amount of energy, then that stable starting position is defined as the ground state.

If atoms move or collide frequently, or if the star spins, then the Doppler shifts from different parts of the gas smear the lines out; if magnetic fields are present, they split the lines into multiple components.