Question

1. In a very general way, describe Fraunhofer lines.

2. Given what you learned in your research, how could Fraunhofer lines help William Huggins determine the composition of stars in the 1880s?

3. What happens when you put the spectrascope toward the cloud or white paper in the sun,do you observe Fraunhofer lines?

Answer 1

1. Fraunhofer lines are some dark lines seen in the spectrum of sun or other star. It is due to the selective adsorption of radiation at specific wavelenghths by varoius elements in the atmosphere.

2. Spectra of different stars were not identical. Dark lines are produced by the chemical elements in the stars. By analysing the spectra we will get an idea about the chemical elements. Stellar spectra depends on the temperature of the stars also.

3. We can use spectroscope to look at the sunlight reflected off white clouds or white paper to see the spectrum of sun. We can see dark lines in the solar spectrum. These are Fraunhofer lines.