Question

The bright line emission spectrum shown above is characteristic of the region of the nebula marked in the drawing. By comparing the positions of the lines in the spectrum to a known laboratory spectrum on Earth, which of the following properties of the nebula can be directly determined?

a. Motion towards or away from Earth only.
b. Temperature only.
c. Chemical composition (type of atoms) only.
d. Motion and chemical composition.
e. Motion, temperature, and chemical composition.

Answer 1

By knowing the shift in the wavelength of light from nebula as compared to the wavelength of spectrum of known material,we can determine that its spectrum gives red shift or blue shift and hence we can conclude that nebula is moving away or towards the earth(by Doppler shift).

We can also determine its temperature by using wien's displacement law.

We can also compare the spectral lines with the spectrum of know material and in this way we can determine the chemical composition of nebula.

So we can say that among the given options ,option (e) is correct.