Which statement best describes plastic's ability to conduct electricity? a) they are good insulators because their atoms have a single loosely bound electron in the outer shell that can move freely between other atoms. b)they are good insulators because they have electrons that are tightly bound in their shells which makes them unable to move between other atoms. c)they are poor insulators because the electrons in the atom are tightly bound and unable to move between other atoms. d)they are poor insulators because the electrons are able to move freely between the different energy levels within the atom.

The correct answer is B)

Everybody this is te correct answer

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.