In general, the narrower the spectral line of a star
A.the hotter the star is
B.the bigger the star is
C.the denser the star is
D.the smaller that star is
E.the cooler the star is
http://en.wikipedia.org/wiki/Stellar_classification
Well, when it comes to the narrower spectral line of a star, you could say that it's like a really thin hot dog. So, it's not about being bigger or denser. And no, it's not about being cooler either. So, if you had to pick an option, I'd say choose A - the hotter the star is. Just like a skinny hot dog, a narrower spectral line suggests a high temperature.
The correct answer is A. The narrower the spectral line of a star, the hotter the star is. This is because the width of a spectral line is related to the velocity of the atoms or molecules emitting the light. In a hot star, the atoms or molecules are moving at higher velocities, causing the spectral lines to be narrower. Conversely, in a cooler star, the atoms or molecules are moving at lower velocities, resulting in broader spectral lines.
To determine the correct answer, we need to understand how the spectral lines of a star are related to its properties. Spectral lines are the dark or bright lines that appear in a star's spectrum when its light is broken down by a spectroscope. These lines are caused by the absorption or emission of specific wavelengths of light by elements and molecules in the star's outer layers.
The width or narrowness of the spectral lines can provide information about the physical properties of the star. A narrow spectral line indicates that the elements or molecules responsible for the line are moving at a relatively uniform speed. On the other hand, a broad spectral line suggests that these particles have a wide range of speeds.
Now, let's consider the given options:
A. The hotter the star is: It is incorrect to directly associate the narrowness of spectral lines with the temperature of a star. The temperature of the star primarily determines the overall shape and color of its spectrum, not the narrowness of the lines.
B. The bigger the star is: The size of a star doesn't have a direct correlation with the spectral line width. The size of a star affects other properties, such as its luminosity and surface gravity, but not the narrowness of spectral lines.
C. The denser the star is: The density of a star is not directly related to the narrowness of its spectral lines. The density mainly affects the pressure and composition of a star, which can influence its overall spectrum but not the width of individual spectral lines.
D. The smaller that star is: This option is also incorrect. The size of a star doesn't have a direct impact on the narrowness of its spectral lines.
E. The cooler the star is: The correct answer is E. The cooler the star is, the narrower its spectral lines tend to be. This is because cooler stars have lighter atoms or molecules in their outer layers, which have lower thermal velocities. As a result, the particles responsible for the spectral lines will have less random motion, leading to narrower lines in the spectrum.
To summarize, the narrower the spectral lines of a star, the cooler the star is (Option E).