Question

The solar spectrum in general is:
A. radiation spectrum
B. absorption spectrum
C. emission spectrum
D. continuous spectrum

Answer 1

Hint: Firstly, you could think of the formation of the solar spectrum. Remember that after leaving the sun’s surface the light from the sun is passing through the Sun’s surface and also several layers in which lots of gases are present. Then, you could identify the answer from the given option and then give a brief justification.

Complete answer:
In the question we are asked to find which among the given options best describes the solar spectrum in general.
In the year 1801, William Wollaston observed a rainbow closely and noticed dark lines in the visible spectrum. Years later in 1817, it was Fraunhofer who observed the sun spectrum which comprises IR, UV and visible regions of electromagnetic spectrum closely by expanding it onto a huge wall and found the missing slices. These are the absorption lines which were later named as Fraunhofer lines after the scientist who discovered them. Hence, we could say that the solar spectrum is made of a continuum of thousands of dark absorption lines. The solar spectrum is even called the Fraunhofer spectrum sometimes.
Therefore, we could conclude that the solar spectrum in general is an absorption spectrum.

Hence, option B is found to be the correct answer.

Additional information:
Absorption lines are in general caused due to the transition of an electron between different energy levels of an atom. Every element has a specific pattern of absorption lines and thus we could identify the existence of a particular element if the pattern observed in that area matches the known spectrum of the element.

Note:
The sun’s spectrum is actually nearly continuous when sunlight leaves the surface of the sun. But after that it is passing through the Sun’s atmosphere where numerous gases are present that absorbs specific wavelengths of this light. From the observed pattern of the spectrum we could actually identify the gases that are present in the Sun’s atmosphere.