Answer:
The option is B is not true for Hubble telescope.
<span>A cumulus cloud is puffy and white.
</span><span>Vinegar has a very sour smell.
</span><span>Water boils at 100 degrees Celsius. </span>
Answer:

Explanation:
Refractive Index: It is a measure to find how fast the light travels through a medium. It is ration of the speed of light in vacuum to speed of light in the medium. Speed of light is not constant and varies depending on the density of the medium.
In vacuum the speed of light is 300000 km/s and is denoted by c. When the light beam enters any medium the speed will decrease. Here it is given that the speed in plastic is v. Thus the refractive index(n) is given as:

It is a dimensionless no.
In physical science, tension can be described as the motion that applies a pulling force that is transmitted axially through cables, chains, or string. On the other hand, compression is the application of balanced inward forces while extension is the application of balanced outward forces in the same axis through the object.