Astudent takes notes in class.
sound waves
i. created by a vibration
a. vibration: something that causes air molecules to move back and forth quickly and steadily
ii. move through a medium
a. solid
b. liquid
c. gas
which line of her notes contains an error? i i a ii b ii c

 IA (the answer is not among the given options)

Explanation:

While it is true that the sound depends on a medium to move, its speed will depend on the medium, whether solid, liquid or gas.

It is also true that sound waves are mechanical vibrations, in this sense, vibrations of molecules do not only occur in the air (gaseous medium), but also in solids and liquids, which makes the propagation of sound possible in the respective media.

Therefore, the line that contains error is IA

lA

Explanation:

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.