The refractive index of a material is a dimensionless number that describes how fast light travels through the material. It is defined as n={\frac {c}{v}}, where c is the speed of light in vacuum and v is the phase velocity of light in the medium.
the ratio of the velocity of light in a vacuum to its velocity in a specified medium.
Answer: the correct answer is (B) He did not know that interstellar dust made it hard from him to see a large part of the Milky Way's disk.
Explanation:
We live in a dusty Galaxy. Because interstellar dust absorbs the light from stars, Herschel could see only those stars within about 6000 light-years of the Sun.
Answer:
https://www.slader.com/discussion/question/an-electron-is-accelerated-through-240-times-103-v-from-rest-and-then-enters-a-uniform-170-t-magnetic-field-what-are-a-the-maximum-and-b-the-9e425fbd/
( Here is solution)
The force exerted by a pressure of any gas over a surface its given by the formula P=F/S (where P is pressure, F force and S surface).
We can multiply both sides of the formula by S to obtain the force.
P*S=(F*S)/S
P*S=F
Solve for P=1.80*10^5 Pa and S=4.10*10^-4 m^2 ([Pa] =[N/m^s])
(1.80*10^5 N/m^s) * (4.10*10^-4 m^2) =F
73.8 N =F
Hard surfaces reflect sound back into the room, while carpets help to absorb the sound so it reflects less
