<span>The answer is heterogeneous mixture. A heterogeneous mixture is a combination of substances that are combined physically but not chemically. This is a mixture that is not uniform in composition. Its components can easily be separated from one another. For example, pile of soil is a heterogeneous mixture because it consists of different components.</span>
In a spectrograph, black lines can be seen going through the array of colors. The pattern of these lines indicate the composition of the star.
Different elements block different parts of the spectrum, resulting in black lines.
From the Hooke's law , the extension force of an elastic material is directly proportional to the extension.
That is, F = k e, where F is the force , k is the constant and e is the extension
F = 10 × 10 = 100 N
e = 1mm or 0.001 m
Hence, k = F/e
= 100 N/ 0.001
= 100000 N/m or 100 N/mm