Why sunlight produces more spectral lines than other light sources
Spectral lines
FYI. There are spectral emission lines and spectral absorption lines.
If you can describe what you're studying I may be able to guess where you're going with this.
Otherwise, here is link that may get you started.
http://phet.colorado.edu/en/simulation/blackbody-spectrum
Sunlight produces more spectral lines than other light sources because it is a broad-spectrum light source, meaning it emits light across a wide range of wavelengths. Other light sources, like incandescent or fluorescent lamps, typically emit light at specific wavelengths or in a limited range.
The reason sunlight contains a wide range of wavelengths is because it is emitted by a hot, glowing object - the Sun. As the Sun's surface temperature is around 5,500 degrees Celsius (9,932 degrees Fahrenheit), the atoms and molecules in its outer layers are in an excited state. This high temperature causes the electrons in these atoms and molecules to become more energetic, moving to higher energy levels.
When the electrons eventually return to their original energy levels, they release the excess energy in the form of light. The specific energy difference between the energy levels determines the wavelength of the light emitted. Since there are countless atoms and molecules in the Sun's outer layers, with varied energy differences between their energy levels, a wide variety of wavelengths are emitted, resulting in a continuous spectrum.
When this sunlight reaches Earth, it passes through the Earth's atmosphere, which contains various gases, including oxygen, nitrogen, and trace elements. These gases can absorb certain wavelengths of light, leading to the formation of dark absorption lines in the spectrum. These absorption lines correspond to the specific wavelengths of light that were absorbed by the gases in the atmosphere.
To observe the spectrum of sunlight with its numerous spectral lines, you would need a device called a spectrometer. A spectrometer disperses the incoming light into its different wavelengths, allowing you to measure and analyze the specific wavelengths and their intensities. By analyzing the resulting spectrum, scientists can gain valuable information about the composition and properties of the Sun, as well as atmospheric conditions on Earth.