I will mark you Brainlient The particles of a substance vibrate in place but stay in fixed positions. When thermal energy is added to the substance, the particles stay close together but start to slide past one another. What change in state has occurred?

O A. Solid to gas
OB. Solid to liquid
O C. Liquid to gas
OD. Liquid to solid

d.solid to liquid cause they were once on a fixed and started to slide.liquid particles slide along a container so it is a solid to liquid

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.